EP0835958A2 - Grain distribution for ballast for a railway track ballast - Google Patents

Abstract

The ballast is lifted and processed to remove particles below a set minimum diameter. The mix of particle sizes in the cleaned ballast is determined and new ballast and chippings are added to obtain an optimum mix which will provide a good lateral support for the rails water drainage. The ballast mix provides more contact with the sleepers. The particle size has a minimum of 2 to 8 mm, with an absolute minimum of 2 mm. The particle size mix follows a programmed characteristic.

Description

The invention relates to a ballast composition for a Railway track bed, especially for a track bed with at least Shares from refurbished old gravel. Under old gravel Such a gravel is called here, which already was installed in a track bed and for processing has been excavated.

It is an object of the invention to process old ballast in such a way that as large a portion as possible be reusable Ballast can be returned to a track bed. A Another goal is an extremely stable track ballast to generate regardless of whether New and / or old gravel is used as the starting material.

A recycling of refurbished old ballast will already practiced.

• eine Reduzierung künftiger Setzungen und Setzungsdifferenzen innerhalb des Gleisbettes,
• auf eine Erhöhung des Querverschiebewiderstandes innerhalb des Gleisbettes,
• auf eine Erhöhung der Kontaktstellen zwischen den einzelnen Schottersteinen und des Schotters mit den Schwellen des Gleises,
• auf eine Reduzierung der Kanten- und Kornbruchgefahr bei den einzelnen Schottersteinen.

Proceeding from this, the invention is concerned with the problem of improving the track stability in the case of a refurbished track bed, in particular when there is a high proportion of old ballast. The improvement should relate in particular to

• a reduction in future subsidence and settlement differences within the track bed,
• to an increase in the transverse displacement resistance within the track bed,
• an increase in the contact points between the individual ballast stones and the ballast with the sleepers of the track,
• on a reduction in the risk of edge and grain breakage with the individual gravel stones.

Furthermore, the cleaning interval, that is the Period after each cleaning or refurbishment the gravel bed is required have been extended. Polluting Substances are said to be used in the processing of old ballast removed and properly disposed of this share on a limitation of the actually polluting Substances should be kept as low as possible.

According to the invention, the above-mentioned goals are achieved a ballast composition according to the characteristic features of claim 1.

The non-uniformity number U is in DIN 1080, part 6, terms, Formula symbols and units in construction, defined. It is determined from the grain size distribution according to DIN 18123, determination the grain size distribution. The water permeability value is also defined in DIN 1080, part 6 and is in accordance with DIN 18130, Part 1, determination of the water permeability value, determined.

The DIN standards listed are exclusive at the time of filing this patent application valid version referred. Others, that is, earlier ones or later versions are not intended to influence the content own the invention.

With this composition is when using old gravel usually add new ballast and new split to this. A gravel with such a composition is installed in a track in the usual way. On compliance the characteristic features must be observed.

The lower limit for the mean grain diameter of each Gravel stones can advantageously also below of 8 mm and in particular 5 mm or even at 2 mm.

A very important criterion is the realization of a relative flat grain distribution line in contrast to the previously known steeper characteristic curves. With the so far the non-uniformity number was used U always below the value 2. In the case of the invention Ballast composition has a ballast bed higher than the prior art Densities and higher dynamic stability.

While according to the invention gravel stones with medium grain diameters can be used from 2 mm and for So far, a particularly good result has been achieved Ballast stones with grain diameters below 10 mm not in a new or refurbished ballast bed has been added.

The composition according to the invention is equally suitable Way for new and refurbished old gravel. Should at the processing of old ballast for practical reasons no gravel stones with grain diameters up to a lower limit of 2 mm can be screened - for example because of a suitable sieve clogging damp and / or dirty old ballast - this is the proportion of ballast with the smallest grain diameters, possibly in unproblematic Way to admit as new gravel.

An example of a grain distribution according to the invention is in shown in the drawing.

Claims (3)

Ballast composition for a railway track bed, in particular for a track bed with at least portions of refurbished old ballast,
characterized by the characteristics, the individual gravel stones have average grain diameters with an upper limit of 65 mm and a lower limit in a range between 8 and 2 mm, a non-uniformity number of U = d ₆₀ / d ₁₀ ≥ 3 according to DIN 1080 in connection with DIN 18123 applies to the grain distribution, the grain size distribution does not have any grain size, i.e. the grain size distribution line runs almost continuously, the ballast bed has a water permeability coefficient of k ≥ 1 x 10 ^-2 m / s. Ballast composition according to claim 1,
characterized,
that the lower limit of the mean grain diameter is in a range between 5 and 2 mm. Ballast composition according to claim 1 or 2,
characterized,
that the lower limit of the average grain diameter is 2 mm.

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