US1969311A

US1969311A - Turbine locomotive

Info

Publication number: US1969311A
Application number: US714226A
Authority: US
Inventors: Lysholm Alf; Boestad Gustav Karl William
Original assignee: Ljungstroms Angturbin AB
Current assignee: Ljungstroms Angturbin AB
Priority date: 1933-02-23
Filing date: 1934-03-06
Publication date: 1934-08-07
Anticipated expiration: 1951-08-07

Description

1934- A. LYSHOLM El AL 1,969,311

TURBINE LOCOMOTIVE Fild March 6, 1954 4 Sheets-Sheet 2 I INVENTORS BY dv.

MATTORNEY Aug. 7, 1934. A. LYSHOLM ET AL 1,969,311.

TURBINE LOCOMOTIVE Filed March 6, 1934 4 Sheets-Sheet 3 //8 II, w

v INVENTORS '6 0 fl r/ATTORNEY Aug. 7, 1934.

A. LYSHOLM El AL TURBINE LOCOMOTIVE Filed March 6, 1934 4 Sheets-Sheet 4 EC E I r. QQ INVENTORS BY d f d4 MATTQRNEY latented Aug. 7, 1934 PATENT OFFICE TURBINE LOCOMOTIVE A]! Lysholm,

William Boestad, Lidingo, Sweden, Aktiebolaget Ljungstriims Stockholm, and Gustav Karl assignors to. Angturbin, Stockholm, Sweden, a corporation of Sweden Application March 6, 1934, Serial No."i14,226 Germany February 23, 1933 19 Claims. (CL 105-38) The present invention relates to turbine locomotives and has particular reference to turbine locomotives of thekind in which separate forward and reversing turbines are employed. Still more particularly, the invention relates to turbine locomotives of the kind in which power from the forward and reversing turbines is transmitted to a driving axle of the locomotive through the medium of a train of speed reducing gears.

The general object of the invention is to provide novel and improved structure whereby geared drive to a driving axle of the locomotive may be efiected in an improved manner. More particularly, in one of its aspects, the invention has for an object the provision of a novel arrangement of reversing turbine whereby efficient operation of the locomotive in reverse is obtained when it is propelled by a very simple and inexpensive separate reversing turbine. In another aspect the invention has for a more specific object the provision of a new and improved arrangement of gearing and turbine parts whereby improved weight distribution of the locomotive driving mechanism is effected.

The more specific nature of the invention, together with other and more detailed objects thereof may best be understood from a consideration of the-ensuing description of a preferred form of turbine locomotive embodying the invention illustrated in the accompanying drawings forming a part of this specification.

In the drawings:

Fig. 1 is a cross section, partly in elevation, looking forward of a locomotive having driving mechanism constructed in accordance with the invention;

Fig. 2 is a more or less diagrammatic plan view, partly in section, of part of the drivmg .mechanism shown in Fig. 1;

Fig. 3 is a diagrammatic representation illustrating the gear arrangement and taken on line 3-3 of Fig. 2;

Fig. 4 is a sectional view on enlarged scale taken on the line 44 of Figs. 2 and 3;

Fig. 5 is a sectional view on an enlarged scale taken on the line 55 of Figs. 2 and 3;

Fig. 6 is a transverse section taken on the line 6-6 of Fig. 5;

Fig. 7 is a section taken generally on the line 'l--'I of Fig. 3;

Fig. 3 is a section on a still larger scale of the reversing turbine and gear structure shown in Figs. 1, 4 and 5; and

the cranks set at the usual angle of erally at 32 is rigidly Fig. 9 is a diagram illustrating efiiciencies of turbine operation,

Referring more particularly to Figs. 1 and 5, the locomotive boiler is indicated generally at 10 and is carried on the usual locomotive frame comprising the

side frames

12 and 14. 16 designates one of the driving axles of the locomotive of which there may be a plurality, the number varying with the sire and type of the locomotive. Advantageously axle 16 is the forward driving axle although this is not essential to the present invention. One pair of locomotive driving wheels is indicated by reference numerals 18, the drivers being fixed to axle 16 in the usual manner.

In the embodiment illustrated, drive to the remaining driving axles is efiected through side rods and for this purpose crank arms 20 and pins 22 are fixed to the ends of axle 16, with 90 with respect'to each other. Also, in the present em- I bodiment the longitudinal driving thrust between the driving axle and the frame is taken up by side links indicated at 24 and 26. Vertical support of axle 16 with respect to the frame is provided at 28 and 30 by journal and spring structure, which has been omitted from the drawings for the sake of simplicity.

The main or forward turbine indicated genmounted on an extension 34 forming part of the frame of the locomotive and, as is evident from the figures, this turbine is situated well to the right of the center line of the locomotive as viewed in Fig. 1. At the opposite side of the locomotive the reversing turbine, indicated generally at 36, together with a primary reduction gear indicated generally at 38, is secured to an extension 40 of the locomotive frame. A'secondary reduction gear, indicated generally at 42, is carried in the locomotive frame between the

side members

12 and 14. The casing 130 of the secondary gear 42 is carried independently of the casing 39 of the primary gear 38, and may advantageouslybe mounted, as shown in Fig. 3, by. means of pivot pin and link connections indicated generally at 131 and 133, which serve to support the casing from suitable frame parts indicated at 135 and 137. A pin connection is advantageously employed in conjunction with the link connection 133 to hold the casing 130 in proper longitudinal alignment in the locomotive frame.

Referring now. more particularly tov Figs. 2 and 3, the mechanism for transmitting drive from the turbines to the driving axle will be described. From the forward turbine 32 drive is transmitted through shaft 44 which extends transversely across the locomotive to the primary reduction gear 38. This reduction gear, in the present embodiment, comprises a double pinion 46 on shaft 44 meshing with twin double gears 48 and 50. Gears 48 and 50 are mounted respectively on the

transverse shafts

52 and 54, and at the ends opposite the gears 48 and 50 these shafts carry respectively the

pinions

56 and 58, meshing with the gear 60 comprising a part of the secondary gearing. The secondary gearing comprises, in addition to

pinions

56 and 58 and the gear 60, the axle gear 62, which meshes with gear 60. Gear 62 is not mounted directly upon axle 16, but is connected thereto through the medium of an articulated connection to be described later.

The reversing turbine is placed above the primary gearing and the shaft 64 of this turbine (see Fig. 3) carries a pinion 66 meshing with gear 68 journaled in casing 86 and loose about the extension 82 of shaft 44 to transmit drive in reverse direction to this shaft.

Turning now' to Fig. 4, the forward turbine is shown as having an inlet 70 for the admission of steam to the blade system of the turbine, which, in the present embodiment, comprises a few stages'of impulse blading shown at 72 and a plurality of stages of reaction blading shown at 74. Within the scope of the invention the character of the blading employed-in the forward turbine may vary widely. The turbine rotor, which includes a shaft part '76, is

advantageously connected to the transverse shaft 44 by a flexible diaphragm coupling '78, and shaft 44 is connected by means of a diaphragm coupling to a shaft part (see F g. 8) 82, which is in effect an extension of shaft 44. Gear 68 has a hollow hub through which shaft part 82 loosely passes, and suitably fixed to the end of this shaft part is the double pinion 46. Pinion 46 may advantageously have elongated teeth which provide a certain degree of tooth resiliency, and the pinion is mounted in suitable journal bearings 84 in the primary gear casing indicated generally at 86. Rigidly attached to the primary gear casing 86 is the reversing turbine 36, which is of relatively simple form, comprising a comparatively few stages of turbine blading indicated generally at 88, to which steam is admitted through the inlet 90. The rotor shaft 64 of the reversing turbine carries the pinion 66, the shaft being mounted in the journal bearings 92 carried by the primary gear casing 86.

Pinion 68 is journalled at 94 in the primary gear casing and the hub of this gear is provided with an extention 96 which is externally splined as indicated at 98 and carries the sliding sleeve 100. At one end, sleeve 100 is provided with internal teeth 102 adapted to mesh with teeth 104 fixed on the driving shaft part 82, and also is provided with a peripheral slot 106 in which are located the arms of a shaft fork indicated at 108. As will be evident from the drawings, the sliding sleeve 100 and teeth 102 and 104 provide a releasable coupling for the reverse turbine which is in the form of a claw or dog clutch. Within the scope of the invention'other forms of releasable couplings may I be employed.

gears 48 and 50 of the primary gearing, gear 48 appearing in Figs. 4 and 8, and as will be evident from Fig. 4, gear 48 (and also gear 50) are journalled in the primary gear casing v86. The primary gear casing 86 may advantageously comprise an extension 110 (Figs. 4 and 8) for the protection of shaft 44 and the flexible joints associated therewith. As shown more clearly in Fig. 7, the gears 48 and 50 are advantageously resilient. In this figure, gear 48 is shown in section and a description of this gear will serve for both. The gear comprises a hub portion 112 journalled in primary gear casing 86 and a separate rim portion 114 carrying the gear teeth. Hub 112 has a central. radially extending web 116 engaged by a plurality of peripherally spaced transverse springs 118, which at their ends engage side rings 120 and 122. The side rings 120 .and 122 are fixed rotationally' with respect 'journalled in the secondary gear casing 130.

Similarly, shaft 54, driven from the hub of the flexible gear 50, is connected by means of a flexible coupling to pinion 58, which is also carried in the secondary gear casing 130.

In Fig. 4, gear 60, with which pinions 56 and 58 mesh, is shown, this gear being journalled at 132 in the secondary gear casing 130.

In Fig. 5, gear 62 is shown, which is journalled at 134 in the gear casing 130, and as will be seen from this figure the hub 136 of this gear is extended as at 138 through the gear casing. The extension 138 has rigidly secured thereto the cross arm 140 (see also Fig. 6), which is forked at its ends as shown at 142. The axle 16 has rigidly secured thereto the cross arm 144, which at its ends is forked as shown at 146. A third cross arm 148 is provided with a central opening 150, larger in diameter than the axle 16, throughwhich the axle passes, and I the ends of the

cross arms

140, 144 and 148 are connected by a plurality of articulated links 152 for transmitting drive from the cross arm 140 to the cross arm 144.

The above described construction is not new per se, and permits drive to be transmitted from the secondary gearing to the driving axle without having destructive stresses set up due to angular movement of the driving axle 16 in a vertical plane with respect to the locomotive frame.

Other specific details of construction may be employed within the scope of the invention for effecting drive from the secondary gearing to the driving axle, and other arrangements for obtaining resiliency of drive may also be employed, although for reasons which will hereinafter be pointed out, the arrangement herein shown for obtaining resilience of drive is to be preferred in many instances. With respect to the arrangement of the gearing as hereinbefore described, the advantages to be obtained may be briefly summarized as follows: for locomotives of large size and power, the subdivision of the gearing into primary and secondary reduction gears separated from each other and carried separately, permits of gear transmission of power from the turbine to the driving axle, whereas such gear drive would not be possible for such large sized locomotives if it were attempted to provide the usual unitary type of gearing. Also, as will be evident from the drawings, the division of the gearing in accordance with the invention permits the placing of ,the heavy slow-speed secondary gearing centrally of the locomotive between the side frames, and further permits the balancing of the weight of the driving mechanism for the locomotive by placing primary gearing at one side of the locomotive opposite to and in balancing relation with respect to the main turbine. This arrangement of the primary gearing further permits of the advantageous use of a separate reversing turbine, which may be readily connected into the gearing by means of a releasable coupling, the advantages of which will be pointed out later. The arrangement also permits the ready use of dual driving shafts for transmitting drive from the primary gear to the secondary gearing, and this in turn is of substantial advantage since it enables the secondary gears to be made much narrower than would otherwise be possible. The narrow secondary gears possible with this arrangement contribute substantially to the pos sibility of placing the heavy secondary gearing in the cramped space between the side frames of the locomotive.

In high speed heavy duty locomotive gearing it is highly desirable to provide resilience in the line of drive between the turbine shafts and the driving axle, and by making the intermedi-.

ate gears in the primary gearing of resilient form, and further by providing dual gears, it is possible to provide resilient drive without difliculty because of the fact that the torque transmitted through these intermediate gears is much less than the torque which is transmitted through the slow moving secondary gears. While it is possible to provide resilient drive in the secondary gears in gearing up to certain capacities, the high torque values which must be transmitted through the resilient mechanism when it is incorporated in the secondary gears makes the latter arrangement less desirable in substantially all cases, and practically impossible in gearing where the power to be transmitted is that which is required for very large and heavy locomotives. Separation of the parts of the gearing into separately housed primary and secondary reduction gears also facilitates the most advantageous lubrication of the gearing,

since the primary gear casing may be filled with relatively light lubricant best suited for lubrication of the primary gears which operate at relatively high speed/while the seconda y gear casing may be filled with a relatively heavy grade of lubricant more suited for lubrication of the relatively slow speed secondary gears.

As will be evident from the drawings, the separate reversing turbine is connected into the main driving gear train through an additional speed reducin gear comprising the pinion 66 and gear 68. us, the reversing turbine, at a given locomotive speed, operates at a considerably higher speed than the forward turbine. In the, embodiment illustrated the gear ratio between the shaft of the reversing turbine and the shaft which operates at-the same speed as the forward turbine is approximately 3 to 1. This gearing of the reverse turbine constitutes an important feature of-the invention, since of the turbine.

it permits the obtaining of highly desirable efliciency characteristics for the reverse turbine.

As is well known in the turbine art, the efficiency of a turbine is indicated by what .is known as the Parsons figure of the turbine. This figure is arbitrary, and is determined by the sum of the squares of the peripheral speeds of the turbine blades divided by the heat drop The sum of the squares of the blade speeds is usually designated as Zu and the larger this factor with respect to the heat drop through the turbine, the higher is the Parsons figure. Generally speaking, the higher the value of the Parsons figure for a given turbine, the higher the efliciency thereof. It is" obviously desirable to have the reversing turbine operate with high efiiciency, and by gearing the separate reversing turbine so that it operates at a higher speed than the forward turbine, it is possible to provide a reversing turbine with. relatively few stages as compared with the stages necessary in the forward turbine, which will at the same time operate with higher efllciency. This in turn permits an acceptable reversing turbine to be constructed which is relatively low in cost, and because of the low cost of a reversing turbine of this character, it is economically possible to provide a turbine drive for a locomotive in which two separate turbines are employed instead of a drive of the type in which a single turbine is employed in conjunction with reversible gearing in order to obtain both forward and reverse drive. The arrangement according to the present invention provides a cheaper and more practical construction, particularly for large locomotives, than construction employing a single turbine with reversible gear- In order to illustrate the effect of providing a separate reversing turbine geared as in accordance with the present invention, reference may be made to the curves shown in Fig. 9. In the diagram the abscissa: represent locomotive speed, and the ordinates represent turbine efficiency. The solid line curve a indicates the efliciency at various locomotive speeds of the forward turbine. The dotted line curve 1) illustrates the efliciency which would be obtained with a reversing turbine having comparatively few stages if the reversing turbine were geared to I25 operate at the same speed, relative to locomotive speed, as that of the forward turbine. The dotdash curve c indicates the efliciency obtainable with a smaller reversing turbine having relatively few stages when it is geared approximately in accordance with the hereinbefore described embodiment of the invention, with the reversing turbine operating at about three times the speed of the forward turbine, with respect to locomotive speed. 7

When consideration is taken of the fact that locomotives rarely, if ever, operate in reverse at a speed greater than half the maximum forward speed, it will be evident "that operation in reverse with a turbine having an efficiency curve similar to curve b would be very unsatisfactory,

since in the range of speed where the reverse turbine is generally operated, the' efllciency is relatively very low as compared with the eiliciency of the forward turbine. accordance with the present invention, a relatively small turbine is geared to an extreme speed providing the high efliciency at low locomotive speed as indicated by curve c, the small If, however, in

and relatively simple and cheap reversing turbine provides a satisfactory medium for effecting reverse drive.

The provision of the releasable coupling between the reversing turbine and the main portion of the gearing enables the reversing turbine to remain idle when the forward turbine is in operation, which is ordinarily by far the greater proportion of the time, and the efiiciency of operation with the forward turbine is thus not impaired by windage losses in the high speed reversing turbine. In order to obtain the desired high efliciency in the forward turbine, it is ordinarily necessary to operate this turbine at relatively high speed in order to secure a sufiiciently high value of 211 without having to resort to an impractically large number of stages of the turbine. In a high speed passenger locomotive the forward turbine may operate at speeds of the order of from 8,000 to 14,000 R.P.M. at maximum locomotive speed, and it will be evident that if the reversing turbine were coupled into a gearing when the latter is operated at maximum locomotive speed by the forward turbine, the speed of operation of the reversing turbine would be undesirably high, even when taking into consideration the relatively small diameters of the rotating parts. Accordingly, the releasable coupling which is provided permits the advantages of the kind of reversing turbine employed to be secured without involving serious disadvantages due to excessive speed of operation of the reversing turbine when running idly.

' By connecting the reversing turbine to the gearing in the manner indicated, with the releasable coupling arranged closely adjacent to the reversing turbine, it will be evident that satisfactory coupling and uncoupling of the reversing turbine may be secured with relatively simple coupling means, since the reversing turbine parts to be coupled or uncoupled are of relatively very small mass, and therefore easily controllable. In other words, the difficulties incident to the coupling together of relatively heavy masses having considerable inertia are avoided by the present arrangement. While in the illustrated embodiment a simple dog clutch has been illustrated, it will be evident that other types of clutches may be used with equal facility.

From the foregoing description it will be evident to those skilled in the art that the embodiment shown by way of example herein is subject to considerable change and modification in order to meet the. requirements of individual locomotive designs, without departing from the spirit or scope of the invention, which is to be under.- stood as embracing all forms of structure falling within the terms of the appended claims when construed as broadly as is consistent with the state of the prior art.

What we claim is:

1. In a turbine driven locomotive, a frame having side members, a driving axle mounted in said frame, a turbine, gearing for transmitting power from said turbine to said axle, said gearing comprising a secondary gear casing mounted in said frame between said side members, a set of low speed secondary reduction gears in said casing, a primary gear casing separate from said secondary casing and carried by said frame atone side of the locomotive independently of said secondary gear casing, a set of high speed primary reduction gears in said primary casing, said turbine being carried by said frame independently of said gear casings at the side of the locomotive opposite the first mentioned side, means for transmitting power from said high speed gears to said'low speed gears, and means for transmitting power from said turbine to said high speed gears.

2. In a turbine driven locomotive, a frame having side members, an axle having driving wheels thereon mounted in said frame, a turbine, gearing for transmitting power from said turbine to said axle, said gearing comprising a secondary gear casing mounted in said frame between said side members and encompassing said axle, a set of low speed secondary reduction gears in said casing including a gear around said axle, a primary gear casing separate from said secondary gear casing and carried by said frame at one side of the locomotive independent 1y of said secondary gear casing, a set of high speed primary reduction gears in said primary casing, said turbine being carried by said frame independently of said gear casings at the side of the locomotive opposite the first mentioned side, means for transmitting power from said high speed gears to said low speed gears, and means for transmitting power from said turbine to said high speed gears.

3. ma turbine driven locomotive, a frame having side members, an axle having driving wheels thereon mounted in said frame, a turbine, gearing for transmitting power from said turbine to said axle, said gearing comprising a secondary gear casing mounted in said frame between said side members and encompassing said axle, a set of low speed secondary reduction gears in said casing including a gear around said axle, a primary gear' casing separate from said secondary gear casing and carried by said frame at one side of the locomotive independently of said secondary gear casing, a set of high speed primary reduction gears in said primary casing, said turbine being carried by said frame independently of said gear casings at the side of the locomotive opposite the first mentioned side, non-rigid shaft means for transmitting power from said high speed gears to said low speed gears, and non-rigid shaft means for transmitting power from said turbine to said high speed gears.

4. In a turbine driven locomotive, a frame having side members, a. driving axle mounted in said frame, a turbine for forward drive of the locomotive, gearing for transmitting power from said turbine to said axle, said gearing comprising a secondary gear casing mounted in the frame between said side members, a set of low speed secondary reduction gears in said casing, a primary gear casing separate from said secondary gear casing and carried by said frame at one side of the locomotive independently of said 135 secondary gear casing, a set of high speed primary reduction gears in said primary casing, said turbine being carried by said frame independently of said gear casings at the side of the locomotive opposite the first mentioned side, means for transmitting power from said turbine to said high speed gears and from said high speed gears to said low speed. gears, a reversing turbine carried by said frame at the same side of the locomotive as said primary gear casing, and speed reducing gearing for transmitting power from said reversing turbine to said high speed primary reduction gears.

5. In a turbine driven locomotive,.a frame having side members, a driving axle mounted 1,50

in said frame, a turbine for forward drive of the locomotive, gearing for transmitting power from said turbine to said axle, said gearingcomprising a secondary gear casing mounted in the frame between said side members, a set of low speed secondary reduction gears in said casing, a primary gear casing separate from said secondary gear casing and carried by said frame at one side of the locomotive independently of said secondary gear casing, a set of high speed primary reduction gears in said primary casing, .said turbine being carried by said frame independently of saidgear casings at the side of the locomotive opposite the first mentioned side, means for transmitting-power from said turbine to said high speed gears and from said high speed gears to said low speed gears, a reversing turbine carried by said frame at the same side of the locomotive as said primary gear casing, and means for transmitting power from said reversing turbine to said high speed primary reduction gears comprising a set of reduction gears and a releasable coupling.

6. In a turbinedriven locomotive, a frame having side members, an axle having driving wheels thereon mounted in said frame, a turbine, gearing for transmitting power from said turbine to said axle, said gearing comprisinga secondary gear casing mounted in said frame between said side members and encompassing said axle, a set of low speed secondary reduction gears in said casing including a gear around said axle, an articulated driving connection for transmitting power from the last mentioned gear to said axle, a primary gear casing separate from said secondary gear casing and carried by said frame at one side of the locomotive independently of said secondary gear casing, a set of high speed primary reduction gears in said primary casing, said turbine being carried by said frame independently of said gear casings at the side of the locomotive opposite the first mentioned side, means for transmitting power from said high speed gears to said low speed gears, and means for transmitting power from said turbine to saidhigh speed gears.

7. In a turbine driven locomotive, a frame having side members, a driving axle mounted in said frame, a turbine and gearing for transmitting power from said turbine to said axle, saidv gearing comprising a secondary gear casing mounted in the frame between said side members, a set of secondary reduction gears in said casing, a primary gear casing separate from the secondary gear casing and mounted outwardly of one of said side members and a set of primary reduction gears in said primary gear casing, said turbine being mounted outwardly of the other of said side dual pinions and means for transmitting power from said secondary reduction gears to said driving axle. I

9. In a turbine driven locomotive, a frame having side members, a driving axle mounted in said frame, a turbine mounted at one] side of. the locomotive, a primary gear casing mounted at the opposite side of the locomotive, a set of primary reduction gears in said casing comprisinga plurality of resilient intermediate gears, a secondary gear casing mounted between said side members, a set of secondary reduction gears in said secondary gear casing comprising a plurality of pinions, transverse shafts for transmitting power from said resilient intermediate gears to said pinions, and means for transmitting power from the secondary gears to the driving axle.

10. In a turbine driven locomotive having a driving axle and a frame comprising side members, a secondary gear' casing mounted between gears journalled insaid casing including a plurality of pinions and a gear around said axle and spaced therefrom, articulated means for transmitting power from said gear to said axle,

a set of primary reduction gears at one side of the locomotive comprising a plurality of intermediate gears; and means for separately transmitting power to each of said pinions from said intermediate gears.

11. In a turbine driven locomotive,- a driving axle, a frame having side members-a sec-, ondary reduction gear mounted between said. side members for transmitting power to said axle, a primary reduction gear mounted at one side of the locomotive, power transmitting means connecting said primary and said secondary gears, a forward turbine mounted at the opposite side of the locomotive, means for transmitting power from said turbine to said primary gear, a'separate reversing turbine mounted at'115 the same side of the locomotive as said primary gear, and power transmitting means connecting the reversing turbine and the primary gear comprising reduction gears for causing the reversing turbine to operate at a speed substantiallyhigher than that of the forward turbine for a given locomotive speed.

12. In a turbine driven locomotive, a driving axle, a frame having side members, a secondary reduction gear mounted between said side members for transmitting power to said axle, a pr ary reduction gear mounted at one side of the locomotive, power transmitting means connecting said primary and said secondary gears, a forward turbine mounted at the opposite side of the locomotive, a transverse shaft for transmitting power from said turbine to the primary gear, a separate reversing turbine mounted together with the primary gear, and means comprising a reduction gear for 35 transmitting power from the reversing turbine to said transverse shaft. 1

13. In a turbine driven locomotive, a driving axle, a frame having side members, a secondary reduction gear mounted between said side memhers for transmitting power to said axle, a primary reduction gear mounted at one side of the locomotive, power transmitting means connecting said primary and said secondary gears, a

forward turbine mounted at the opposite side of the locomotive, a transverse shaft for transmitting power from said turbine to the primary gear, a separate reversing turbine mounted together with the primary gear, and means comprising a reduction gear and a releasable coupling for transmitting power from the reversing turbine to said transverse shaft.

14. In a turbine driven locomotive having driving wheels, turbine means for driving said wheels comprising blading for forward drive of the locomotive and blading for reverse drive of the locomotive, and means including speed reducing gearing for transmitting power from said turbine means to said wheels, said gearing including gears providing a greater ratio of speed reduction between all of said blading for reverse drive and said wheels than between any of said blading for forward drive and said wheels.

15. In a turbine driven locomotive having driving wheels, turbine means for driving said wheels comprising blading for forward drive of the locomotive and blading for reverse drive of the locomotive, and means including speed reducing gearing for transmitting power from said turbine 'means to said wheels, said gearing including gears providing a ratio of speed reduction between all of said blading for reverse drive and said wheels at least a plurality of times as great as the ratio of speed reduction between any of said blading for forward drive and said wheels.

16. In a turbine driven locomotive having driving wheels, turbine means for driving said wheels comprising a relatively large number of stages for forward drive of the locomotive and a relatively small number of stages for reverse drive of the locomotive, and means including speed reducing gearing for transmitting power from said turbine means to said wheels, said gearing'including gears providing a greater ratio of speed reduction between all of said stages for reverse drive and said wheels than between any of said stages for forward drive and said wheels.

17. In a turbine driven locomotive having driving wheels, turbine means for driving said wheels comprising a relatively large number of stages for forward drive of the locomotive and. a relatively small number of stages for reverse drive of the locomotive, and means including speed reducing gearing for transmitting power from said turbine means to said wheels, said gearing including gears providing a ratio of speed reduction between all of said stages for reverse drive and said wheels at least a plurality.

of times as great as the ratio of speed reduction between any of said stages for forward drive and said wheels. 7

18. In a turbine driven locomotive having a pair of driving wheels, turbine means comprising a forward turbine providing all of the blading for forwarddrive to said pair of wheels and a separate reversing turbine providing all of the blading for reverse drive to said pair of wheels, and means comprising speed reducing gearing for transmitting power from each of said turbines to said pair of wheels, said gearing comprising gears providing a greater ratio of speed reduction between the reversing turbines and said pair of wheels than between the forward turbine and said pair of wheels.

19. In a turbine driven locomotive having a pair of driving wheels, turbine meanscomprising a forward turbine providing all of the blading for forward drive to said pair of wheels and a separate reversing turbine providing all of the blading for reverse drive to said pair of wheels, and means comprising speed reducing gearing for transmitting power from each of said turbines to said pair of wheels, said gearing'comprising gears providing a ratio of speed reduction between the reversing turbine and said pair of wheels at least a plurality of times as