ZA200808443B

ZA200808443B - Electronic locomotive and method of controlling the same

Info

Publication number: ZA200808443B
Application number: ZA200808443A
Authority: ZA
Inventors: Toshinobu Kanai; Atsuhiko Nishio
Original assignee: Toshiba Kk
Priority date: 2007-10-04
Filing date: 2008-10-03
Publication date: 2009-10-28
Also published as: JP5172266B2; JP2009091409A

Description

ETRE

"2008/05, . - 08.44 3 - J ‘TITLE OF THE INVENTION I

ELECTRIC LOCOMOTIVE AND METHOD OF CONTROLLING THE SAME

BACKGROUND OF THE INVENTION

: : The present invention relates to an electric locomotive used in a freight train to which a plurality of electric locomotives are coupled.

As the freight train structured by coupling many railroad freight cars and having 2 long length of organization, there is a train structured such that locomotives are connected to a front and a rearmost of the train in order to obtain a desired traction force.

In countries having a vast land, the freight train is organized over several kilometers, and there is also operated a long organized train in which the locomotive is connected to’ the midpoint of the train in addition to the front and the rearmost thereof.

For example, in the case of the freight train in which the locomotives are connected to the front and the rearmost, there are an aspect that operators get on both of a locomotive (a main locomotive) in the front " and a locomotive (a helper locomotive) in the rearmost, and an aspect that the helper locomotive is controlled : in an unmanned manner, that is, controlled by a control apparatus. In the case where the operators get on the main locomotive and the ‘helper locomotive, the operator of the helper locomotive communicates with the operator of the main locomotive via radio communication, an air oe vy whistle or the like so as to operate the helper locomotive.

In the case where the helper locomotive is controlled by the control apparatus, the main locomotive sends a power running command (a torque command) and a brake command to the helper locomotive in the organization by a signal sending apparatus, in addition to the main locomotive. As a result, the main locomotive and the helper locomotive are controlled in accordance with the same power running command and brake command.

In the case of the long organized train from several tens of cars to several hundred cars or several kilometers, the main locomotive in the front and the helper locomotive in the rearmost are different in a condition such as a slope, a curve or the like of a railroad on which the train run. For example, in the case of running near a top of a mountainous land or a - hill country, the main locomotive runs on a down slope and the helper locomotive runs on an up slope. : Accordingly, a very large tension is generated in a coupler connecting the cars at an inflection point (near the top in this case) of the slope. Further, in the case of running on a basin or the like, the main locomotive in the front runs on the up slope, and the helper locomotive in the rearmost runs on.the down slope. Accordingly, a very large compression force is

Ce ] oo, generated in the coupler at the inflection point (near a lowest land in this case) of the slope. As mentioned above, the large load is applied to the coupler at the inflection point of the slope. A strength of the coupler is generally designed by setting several tens to about two hundred cars to the maximum value.

Therefore, in the case of the long organized train, it is hard to achieve the longer organization.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to further increase a length of organization of a freight train by using a coupler having the same strength as the conventional one.

A helper locomotive according to the present invention corrects a command from a main locomotive on a basis of its own state detected by a detecting mechanism mounted on the locomotive, and decides a power running command to its motor driving apparatus.

That is, an electric locomotive according to one embodiment of the invention is an electric locomotive applied as a helper locomotive which a operator does not get on in a freight train including a main locomotive operated by a operator, the helper . locomotive being controlled by the main locomotive, comprising: remote control means for receiving information including a power running command from the main locomotive; position detecting means for detecting

Co ey a current position of the helper locomotive; and control means for correcting the power running command received by the remote control means on the basis of the current position detected by the position detecting means, route data and a train length, and controlling its own electric motor driving apparatus on the basis of the corrected power running command.

In comparison with the case of controlling the main locomotive and the helper locomotive on the basis of the same power running command, it is possible to reduce a shock and a load applied to the coupler. This effect becomes significant in the long organized train (having about several km of train length) in which a load over the strength of the normal coupler may be generated. In other words, in accordance with the present invention, it is possible to further increase the length of organization of the train by using the coupler having the same strength as the conventional one.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a view showing a state in which a long organized train passes through a slope inflection point

C in the case where a slope changes from a down slope to an up slope;

FIG. 2 is a view showing a state in which the long organized train passes through a slope inflection point

D in the case where the slope changes from the up slope to the down slope;

FIG. 3 is a view showing an example of an organization of the long organized train to which the present invention is applied;

FIG. 4 is a block diagram showing a structure of a control apparatus 10a of a main locomotive 100;

FIG. 5 is a block diagram showing a structure of a control apparatus 10b of a helper locomotive 200;

FIG. 6 is a view showing a state in which a train to which the present invention is applied passes through a slope inflection point Pa under the condition that the slope changes from the up slope to the down slope;

FIG. 7 is a flow chart showing a concrete example of a torque control operation according to the present invention of a control unit 11; and

FIG. 8 is a block diagram showing a structure of a control apparatus 10c applied to an electric locomotive according to the present embodiment.

DETAILED DESCRIPTION OF THE INVENTION

A description will be given of an embodiment of the present invention with reference to the accompanying drawings.

C in which a slope changes from a down slope to an up slope.

A front car is a main locomotive, and is a car which an operator gets on so as to carry out an operation. A locomotive coupled to a rear portion is a helper locomotive and is an unmanned car on which the operator does not get. Taking an expansion gap of a coupler into consideration, since a force in a reverse direction to a forward moving direction is applied to the cars in an A side of the slope inflection point C in the drawing, and a force in the forward direction is applied to the cars in a B side, an optimum traction force Ts of the helper locomotive does not generally .coincide with a traction force Tm of the main locomotive. However, in a conventional remote control : 20 system, Ts and Tm can not take the other value than the same value. One embodiment of the system in accordance with the present invention solves this problem.

FIG. 2 is a view showing a state in which a long organized train passes through a slope inflection point

D in which the slope changes from the up slope to the down slope.

Both tensile forces in the forward moving direction (in the down slope side) and the reverse direction (in the up slope side) are applied to the coupler at the inflection point D in the drawing. In general, it is often the case that a strength of the coupler is designed by setting a maximum stress generated in an organization having several tens of cars to about one hundred cars to a maximum value. In the case of increasing the length of organization of the train, an increase in a load applied to the coupler at the slope inflection point mentioned above comes to a restriction item against a long organization.

It is effective means for reducing the load to the coupler at the slope inflection point D to couple the locomotive to a rear portion of the organization as shown in an example of FIG. 2. However, in the case of increasing outputs of the individual locomotives as carrying capacity increasing means per organization unit, and increasing the number of the coupled cars, it is impossible to disregard an influence which a temporary stress caused by a wheel idle running of the locomotive and the expansion gap of the coupler gives to the coupler positioned at the inflection point D in

FIG. 2. With regard to the problem mentioned above, the present invention can provide effective solving means.

FIG. 3 is a view showing an example of the organization of the long organized train to which the

: present invention is applied.

The front car of the train is a main locomotive 100, and is a car which an operator gets on so as to carry out an operation. The rearmost car of the train is a helper locomotive 200, and is an unmanned car which the operator is not aboard and which receives a power running (torque) command by the operator of the main locomotive 100 and applies correction to the power running command so as to control its own electric motor driving apparatus. The main locomotive 100 and the helper locomotive 200 are both supplied with an electric power from an overhead wire (not shown) via a pantograph collector 110, and drive their own electric motors so as to run on a rail 111. The several hundred railroad freight cars 101, 102, ..., for example, are coupled between the main locomotive 100 and the helper locomotive 200, and a whole length of the train comes to, for example, several km. As a railroad freight car of the train mentioned above, for example, a bogie railroad freight car is used. The bogie railroad freight car indicates the railroad freight car equipped with a truck (a bogie truck) which is rotatable in a horizontal direction with respect to the car body. The bogie railroad freight car does not have an impediment in a passage of a curve even if the length of the car is elongated, and is suitable for a mass transport of cargo.

N -— 9 —

In the present embodiment, a description will be given of the train in which the helper locomotive is coupled to the rearmost as one example; however, the present invention is not limited to this, but can be similarly applied to a case that one or a plurality of helper locomotives are coupled between the front and the rearmost cars of the train. The main locomotive 100 is equipped with a control apparatus 10a as electric locomotive control means, and the helper locomotive 200 is similarly equipped with a control apparatus 10b.

FIG. 4 is a block diagram showing a structure of the control apparatus 10a of the main locomotive 100.

The control apparatus 10a includes a control unit lla, a remote control apparatus 1lZa and a master controller 13. The control unit lla generates a power running command to an alternating current motor driving apparatus (not shown) of the main locomotive and a brake command to a brake apparatus of the main ~ locomotive on the basis of a power running command and a brake command from the master controller 13, and an actual speed, an actual torque, an actual brake force, an wheel idle running detection and other detection signals detected by various detecting means.

The master controller 13 outputs the power running command and the brake command to the control unit 11 on the basis of an operation signal of a operator (an operator) input from a operation table (not shown).

The remote control apparatus 12a includes a sender for modulating the information including the power running command and the brake command provided from the control unit lla so as to send it to the helper locomotive 200, and a receiver for receiving various modulated information from the helper locomotive 200 so as to demodulate it. The sending and reception of the information are carried out, for example, by a radio transmission.

FIG. 5 is a block diagram showing a structure of the control apparatus 10b of the helper locomotive 200.

The control apparatus 10b includes a control unit 11b, a remote control apparatus 12b, a current position detecting portion 15, and a route data storage portion 14. The power running command and the brake command to the helper locomotive 200 are transmitted to the control unit 1lb from the main locomotive 100 via the remote control apparatus 12b. The control unit 1lb has an internal storage apparatus in which organization data such as a total train length, a total load weight and the like are stored. The route data such as a slope of the route along which the train runs, a position of a slope inflection point, a curvature of the curve and the like are stored in the route data storage portion 14. The current position detecting portion 15 may be constituted by a global positioning

- - 11 = system (GPS) or may be simply constituted by a running distance meter. In the case where the current position detecting portion 15 is constituted by the running distance meter, the control unit 1llb reads the route data from the route data storage portion 14, collates the running distance, for example, from a starting - station to the route data, and detects the current position. In this case, it is assumed that the current position detecting portion 15 is constituted by the

GPS.

The control unit 11lb corrects the power running command and the brake command from the main locomotive on the basis of the current position detected by the current position detecting portion 15, the route data stored in the route data storage portion 14, the organization data stored in the internal storage apparatus and the detection signals such as the actual speed, the actual torque, the wheel idle running direction and the like, and controls the alternating current motor driving apparatus and the brake apparatus of the helper locomotive on the basis of the corrected power running command and brake command. The control unit 11b can send the power running and brake commands for the helper locomotive to the main locomotive 100 via the remote control apparatus 12b. Further, the control unit 1lb can input abnormality detection signals from sensors detecting a motor temperature i. - 12 - abnormality, a fire disaster, a disconnection or the like, and can send the abnormality detection signals as various information to the main locomotive 100 via the remote control apparatus 12b. Accordingly, the main locomotive can comprehend an operating condition of the helper locomotive and detect the abnormality.

A description will be given below of one embodiment of a control operation of the control unit 11b. In this embodiment, for simplification, a description will be given of a case that the control unit 1llb corrects the power running command received from the main locomotive 100 on the basis of the current position on the route and the total train length data and controls the helper locomotive. This control is carried out at a time when the train passes through the slope inflection point. Further, in the present embodiment, the power running command is referred as the torque command. The torque command is constituted by a notch command (a phased torque command) which the operator of the main locomotive 100 : gives by the operation table, and is received by a remote control apparatus 12b of the helper locomotive 200 in accordance with radio communication from the remote control apparatus 12a of the main locomotive 100. Further, in the present embodiment, the freight train organized by the railroad freight cars each having the same car body length and the same weight is assumed. In the long organized freight trains handled in the present embodiment, most of them are above type of train, and a freight train for transporting mineral ores and the like is a typical example.

FIG. 6 shows a state in which the train to which the present invention is applied passes through the slope inflection point Pa changing from an up slope to a down slope. In this case, a current position of the main locomotive 100 of the front car is set to Px, a distance from a base point to the current position Px is set to X, and a train length is set to L. The base point indicates, for example, a position of the starting station of the train. Further, a distance from the base point to the slope inflection point position Pa referred in the route data is set to A, a position at which the main locomotive 100 changes the torque command is set to Pb, and a distance from the base point to the position Pb is set to B. A torque command before the change is set to Tl, and a torque command after the change is set to T2. In other words, there is considered a case that the operator reduces the torque command from Tl to T2 at a time point tb when the front car 100 has passed distance “B - A” from an apex (the slope inflection point) Pa of the up slope. For simplification, the train length L is set to a value obtained by simply adding the lengths between the couplers in the respective cars.

The current position Px is detected by the helper locomotive 200 at the rearmost of the train. In other words, the control unit 1llb of the helper locomotive 200 refers to the route data read from the route data storage portion 14, and determines a position on the route which is forward by the train length L from the current position detected by the current position detecting portion 15 as the current position Px of the main locomotive.

In this case, there is considered a condition under which the torque commands of the locomotives 100 and 200 in the front and the rearmost of the train become identical at a time point when the whole organization, that is, the rearmost car 200 passes through the inflection point Pa. In this case, it is "assumed that the torque command of the main locomotive 100 is maintained at T2 until the helper locomotive 200 passes through the inflection point Pa. Since the distance from the base point to the helper locomotive 200 at a time point tb when the torque command is changed is “B - L”, a distance from the inflection point Pa to the helper locomotive 200 comes to A - (B -

L). When the main locomotive 100 exists at the current position Px, the distance from the base point to the helper locomotive 200 is X - L. Accordingly, a : distance from the inflection point Pa to the helper locomotive 200 comes to A - (X - L). As a result, the torque command T of the helper locomotive 200 is controlled as the following expression (1):

T=T1 x [A - (X-L)]/[A- (B-L)] + T2 (1)

In this case, the helper locomotive 200 carries out the torque control during a positional condition where X > A and X < L + A is satisfied.

In more simplification, there is considered a case that the main locomotive 100 passes through the slope inflection point Pa and notches off (torque command value is 0) at the position Pb (B - A < 1). In this case, the torque command value T of the helper locomotive 200 does not simultaneously notch off, but controlled so as to satisfy the following expression (2), and the train moves into a coasting after the helper locomotive 200 pushing up the railroad freight cars in process of the up slope.

T=7T1 x [A-(X-L)]/[A- (B-1L)] (2)

Accordingly, a temporary overload applied to the coupler is reduced at the slope inflection point Pa.

FIG. 7 is a flow chart showing a concrete example of a torque control operation in accordance with the present invention of the control unit 11b.

The control unit 1llb determines, on the basis of the current position provided from the current position detecting portion 15, the route data stored in the route data storage portion 14 and the train length L, whether or not the distance X from the base point of

. - 1l6 - the main locomotive 100 at the front of the train is larger than the distance A from the base point of the inflection point Pa, and smaller than L + A (step

S101). In other words, the control unit 1lb determines whether or not the train is in process of passing through the inflection point position Pa as shown in

FIG. 6. In the case where the train is in process of passing through the inflection point position Pa (YES in step S101), the control unit 11lb sets the current torque command sent from the main locomotive 100 to T1 (step S102).

The control unit 1lb determines in step S103 whether or not any change is occurred in the torque E command from the main locomotive 100, and in the case where the change is not occurred (NO in step S103), the flow goes back to step S101. In the case where any change is occurred in the torque command from the main locomotive 100 (YES in step S103), the control unit 11b sets the torque command after the change to TZ (step

S104).

The control unit 1lb computes the torque command T by substituting the distance X from the base point of the main locomotive 100, the torque command Tl before the change determined in step S102, and the torque command T2 after the change determined in step S104, for the expression (1) mentioned above in step S105.

Further, the control unit 1lb outputs the torque command T to the alternating current motor driving apparatus of the helper locomotive 200 (its own car) (step S106).

The control unit 11b determines in step S107 whether or not the torque command from the main locomotive 100 is changed. In the case where the torque command is not changed (NO in step S107), the control unit 11lb determines whether or not the relation

X >A and X < L + A is established, that is, the train is in process of passing through the inflection point position Pa (step S108). In the case where the train is in process of passing through the inflection point position Pa (YES in step S108), the flow goes back to step S105, and computes the torque command value T of the helper locomotive 200 so as to output it to the alternating current motor driving apparatus (step $106). In the torque command value T computed in this case, since the distance X of the main locomotive 100 is changed in comparison with the previous computed value, the torque command value T is normally changed.

In the case where the torque command from the main locomotive 100 is changed (YES in step S107), the control unit 11b sets the value of T2 determined in step S104 to Tl (step S109), and sets the torque command after the change to T2 (step S104). The control unit 11lb computes the torque command T by : substituting the distance X, the torque command T1 before the change, and the torque command T2 after the change for the expression (1) as mentioned above in step S105, and outputs the torque command T to the alternating current motor driving apparatus of the helper locomotive 200 (its own car) (step S106).

As mentioned above, the control unit 1lb computes the torque command by substituting the torque command values T1 and T2 before the change and after the change, and the distance X of the main locomotive 100 for the expression (1) mentioned above every time the torque command from the main locomotive 100 is changed, and controls the alternating current motor of the helper locomotive 200. Further, the control unit 11lb sets the distance X of the main locomotive 100 to a parameter, computes the torque command by using the expression (1) mentioned above, and controls the alternating current motor of the helper locomotive 200, in the case where the torque command is not changed.

Thereafter, in the case where the torque command from the main locomotive 100 is not changed (NO in step

S107), and the helper locomotive 200 in the rearmost passes through the inflection point Pa (NO in step

S108), the torque control of the helper locomotive 200 is finished.

In the system controlling the locomotive in accordance with the remote control, a method of applying a fixed temporal delay in such a manner as to prevent a sudden torque fluctuation at the time of changing the torque in accordance with the notch , command is known as a so-called jerk control. However, . a method of automatically controlling the torque fluctuation by combining the route information retained in the storage apparatus and the current position information detected by the detecting apparatus such as the GPS, the integral distance meter or the like, as shown in the present embodiment is novel.

The embodiment mentioned above shows the case of the slope change from “up slope” to “down slope”; however, the control method is applicable to the other cases. In short, it is a major point of the present embodiment to change the torque command in accordance with the numerical expression mentioned above in the rearmost locomotive, in the case of detecting the change of the torque command from the front locomotive when the front locomotive is at a position in a range of the distance A + L from the change point Pa of the route condition described in the route data.

The description has been given above of the power running (torque) command control of the helper locomotive 200, but the present invention can be applied similarly to a case of the brake command. For example, in the case where the brake command is applied to an electric brake of an electric motor, the brake command is input as a negative torque command (a notch command) to the control unit 11b. The control unit 11lb can suitably control the brake operation of the helper locomotive by applying the negative torque command value as the torque T in the expression (1) mentioned above. Further, the same applies to a case that the brake command is applied to a mechanical type brake apparatus utilizing friction.

Further, the present invention can be applied to the train in which a plurality of helper locomotives are coupled. For example, in the case where the helper locomotives are coupled to the middle and the rearmost of the train and are independently controlled, the train length L in the expression (1) mentioned above may be set to a distance from each of the helper locomotives to the main locomotive in the front, as one example of the control of each of the helper locomotives.

Next, a description will be given of a second embodiment in accordance with the present invention.

In this second embodiment, the main locomotive in : the front of the train detects the current position, and computes the torque command of the helper locomotive in the rearmost so as to send it by means of radio communication. The organization of the train has the same structure as FIG. 3 shown in the first embodiment.

FIG. 8 is a block diagram showing a structure of a

. - 21 = control apparatus 10c applied to an electric locomotive according to the second embodiment.

The control apparatus 10c is structured such that the route data storage portion 14 and the current position detecting portion 15 which have been already described in FIG. 5 are added in comparison with the control apparatus 10a shown in FIG. 4. In other words, the control apparatus 10c includes a control unit llc, a remote control apparatus 12c, the master controller 13, the route data storage portion 14 and the current position detecting portion 15.

The control unit llc applies correction, on the basis of information such as an actual speed, an actual torque, an wheel idle running detection or the like, to the power running command and the brake command from the master controller 13, and decides the power running and the brake command to its own car. Further, the control unit llc applies correction, on the basis of the current position and the train length, to the power running command and the brake command from the master controller 13, and sends the corrected power running and brake commands to the helper locomotive in the rearmost by means of radio communication.

The correcting operation of the power running command and the brake command of the control unit llc is the same as the operation shown in FIG. 7 basically except the contents of steps S101, S106 and S108. In steps S101 and S108 according to the second embodiment, the position detected by the current position detecting portion 15 is used as it is as the current position of the main locomotive. Further, in step S106 according to the second embodiment, the control unit llc sends the corrected torque T as the torque command to the helper locomotive by means of radio communication.

Since the other steps are the same as those in FIG. 7, a detailed description thereof will be omitted. In the present embodiment, the helper locomotive applies the torque command sent from the main locomotive as it is to the alternating current motor driving apparatus of its own.

Next, a description will be given of a third embodiment in accordance with the present invention.

In this third embodiment, the structure of the control apparatus 10c shown in FIG. 8 is applied to both of the main locomotive 100 and the helper locomotive 200. The control program of the control unit is changed in correspondence to the function of each of the locomotives, and the circuit block is appropriately omitted as occasion demands.

For example, in the case where the control apparatus 10c is used in the first embodiment, the route data storage portion 14 and the current position detecting portion 15 are not used or not provided in the control apparatus of the main locomotive. The master controller 13 is not used or not provided in the control apparatus of the helper locomotive. In the same manner, in the case of using the control apparatus 10c in the main locomotive and the helper locomotive in the second embodiment, the master controller 13, the route data storage portion 14 and the current position detecting portion 15 are not used or not provided in the control apparatus of the helper locomotive.

As mentioned above, it is possible to reduce a manufacturing cost of each of the locomotives and it is easy to manage the locomotive, by using the control apparatus 10c having the same structure in the main locomotive and the helper locomotive, and electrically separating or omitting the circuit block appropriately as occasion demands.

The description mentioned above corresponds to the embodiments in accordance with this invention, and does not limit the apparatus and the method of the invention. Further, various modified embodiments can be easily executed.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, } the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as

F 200 , 8/08443 defined by the appended claims and their equivalents.

Claims

Rim IIe . - 25 ~ . oo ee WHAT IS CLAIMED IS:

1. An electric locomotive applied as a helper locomotive which a operator does not get on, in a freight train including a main locomotive operated by a operator, the helper locomotive being controlled by the main locomotive, comprising: : remote control means for receiving information including a power running command from the main locomotive; position detecting means for detecting a current position of the helper locomotive; and control means for correcting the power running command received by the remote control means on the basis of the current position detected by the position detecting means, route data and a train length, and controlling its own electric motor driving apparatus on . the basis of the corrected power running command.

2. The electric locomotive according to claim 1, wherein the control means comprises: means for determining whether or not the train is in process of passing through a inflection point; means for determining whether or not the power running command received from the main locomotive has changed, in the case where the train is in process of passing through the inflection point; and means for correcting the power running command received by the remote control apparatus on the basis of the power running command before change, the power } running command after change, a distance between the helper locomotive and the inflection point at a time when the power running command changes, and a distance between the helper locomotive and the inflection point at present, in the case where the power running command has changed.

3. The electric locomotive according to claim 1 or 2, wherein a plurality of helper locomotives are coupled to the freight train organization, and each of the helper locomotives corrects the power running command from the main locomotive independently on the basis of the current position of each helper locomotive and the route data.

4. The electric locomotive according to claim 1 or 2, further comprising: detecting means for detecting an abnormal operation, wherein the remote control means sends a signal representing the abnormal operation detected by the detecting means and the power running command corrected by the control means to the main locomotive.

5. An electric locomotive applied as a main locomotive operated by a operator, in a freight train including a helper locomotive which a operator does not get on and controlled by the main locomotive, comprising:

a master controller which outputs a power running command on the basis of an operation signal input from a operation table; position detecting means for detecting a current position of the main locomotive; control means for controlling a motor driving apparatus of the main locomotive in accordance with the power running command from the master controller, and correcting the power running command on the basis of ‘the current position detected by the position detecting means, route data and a train length so as to output the corrected power running command; and remote control means for sending information including the corrected power running command output from the control means to the helper locomotive.

6. The electric locomotive according to claim 5, wherein the control means comprises: means for determining whether or not the train is in process of passing through the inflection point; means for determining whether or not the power running command received from the master controller has changed, in the case where the train is in process of passing through the inflection point and means for correcting the power running command received from the master controller on the basis of the power running command before change, the power running command after change, a distance between the helper

3 - 28 = locomotive and the inflection point at a time when the power running command changes, and a distance between the helper locomotive and the inflection point at present, in the case where the power running command has changed.

7. An electric locomotive in a freight train, applied as a main locomotive operated by a operator and a helper locomotive which a operator does not get on and controlled by the main locomotive, comprising: remote control means for sending and receiving information including a power running command to and from the other electric locomotive; a master controller which outputs a power running command on the basis of an operation signal input from a operation table; position detecting means for detecting a current position; and control means for correcting the power running command from the remote control means or the master controller on the basis of the current position detected by the position detecting means, route data and a train length, and outputting the corrected power running command, wherein the corrected power running command output from the control means is used as the power running command of the helper locomotive.

8. A method of generating a power running command in an electric locomotive applied as a helper locomotive which a operator does not get on, in a freight train including a main locomotive operated by a operator, the helper locomotive being controlled by the main locomotive, the method comprising: receiving information including a power running command from the main locomotive; : detecting a current position the helper locomotive; and correcting the received power running command on the basis of the detected current position, route data and a train length, and controlling its motor driving apparatus on the basis of the corrected power running command.

9. An electric locomotive, substantially as hereinbefore described with reference to the accompanying drawings.

10. Method of generating a power running command in an electric locomotive applied as a helper locomotive, substantially as hereinbefore described with reference to the accompanying drawings. Dated this 3 of October 2008 1 BOWMAN GILFILLAN JOHN & KERNICK : FOR THE APPLICANT