Vocabulaby notes

Read and translate the following sentences into Russian:

1 Broken stone – щебень.

Broken stone is the best material for ballast.

2 Brush – кустарник, заросль, weeds – сорняк, сорная трава.

Ballast prevents the growth of brush and weeds.

3 Cinder – шлак, зола, пепел.

Ashes or cinder, available in large quantities on railways from coal

used in locomotives, have excellent drainage proterties.

4 Crushed rock – дробленый камень, щебень.

Crushed rock, suсh as granite and quartzite, make excellent balla­st and are used in large quantities in India.

5 Depth – глубина, высота, толщина.

depth of ballast – толщина балластного слоя.

With concrete sleepers, certain railways increase the depth of the ballast beneath the sleepers by at least 5 cm.

6 Displacement – перемещение, смещенная осадка,

longitudinal thrusts – продольное усилие,

lateral thrusts – боковое давление, поперечное усилие.

One of the functions of ballast is to prevent sleepers from dis­placement by longitudinal or lateral thrusts.

7 Dust – пыль.

Cinders cannot be used for main lines as it is very soft and pro­duces much dust in the tracks.

8 Gravel – гравий.

Gravel is used as ballast in large guantities in many countries.

9 Yo hold – держать, удерживать.

Ballast holds the sleepers in their correct position.

10 Layer – слой.

The layer of ballast is 24 in below the bottom of the ties.

11 Particle – частица, slag – шлак.

American Railway Engineering Association specifications require that prepared ballast should be crushed stone, slag or gravel composed of hard, strong, durable particles.

12 To prevent – предотвращать.

One should prevent the ballast from being greatly depressed.

13 To provide – обеспечивать.

Ballast provides good drainage.

14 subgrade – земляное полотно, насыпь.

A geophysical method is now being used to check the state of the subgrade.

15 Tamping ~ трамбование, подбивка, уплотнение.

tamper – шпалоподбивочная машина, шпалоподбивщик.

A tamping – levelling – ballast – shaping machine is used for cleaning ballast without removing the track panels.

WORD –BUIUDING

Read and translate the following words.

a) v + er – n

lay – layer

tamp – tamper

support – supporter

read – reader

b) adj. + ty – n

elastic – elasticity

stable – stability

possible – possibility

reliable – reliability

c) v + able – adj.

suit – suitable

consider – considerable

prefer – preferable

move – movable

d) adj. + ly – adv.

uniform – uniformly

general – generally

particular – particularly

relative – relatively

Text 5 a Ballast

Read the text.

Ballast in railway tracks in a layer of broken atone, or other suitable material, under and around the sleepers.

Ballast is used to distribute loads uniformly over the subgrade, to hold the track structure to line and grade, to reduce dust, to prevent growth of brush and weeds and to provide good drainage for the track structure. It provides a suitable foundation for the sleepers in their correct position preventing their displacement by longitudinal or lateral thrusts. Ballast increases the elasticity of the track.

Materials generally used for ballast are crushed rock, washed and screened gravel, slag and cinders. The best ballast consists of very hard broken stone. Asbestos ballast is widely used on some railways now.

The interlocking effect of crushed – rock particles provides a, high degree of stability under the waving action of a moving train. This action tends to produce considerable displacement of rounded particles, particularly at the ends of the sleepers, So, occasional tamping of ballast by hand or with mechanical tampers in roadbed maintenance is needed.

Depth of ballast varies with the supporting characteristics of the subgrade. Relatively unstable subgrade soils will require greater thickness of protective cover. In general the thickness of ballast is about 24 in. below the bottom of the ties. On the railways of the Russia a thickness beneath the sleepers of 20 cm is generally con­sidered as a minimum, but on high speed lines with intense traffic, a minimum thickness of 30 cm is preferable.

It should be noted that the behaviour of ballast depends on different climatic conditions.