Why they put stones on the railway track ?

Question

Why they put stones on the railway track ?

Answer 1

The same reason they put stones under highways.  It provides a firm bed for the rails to rest on and helps distribute the weight of the train over the ground.

Answer 2

The "stones" you refer to are called "ballast".  Some of the answers above are correct, in part.

Ballast actually accomplishes several tasks.  It does provide for drainage along the right of way, but not so the cross ties won't rot.  The cross ties are impregnated with "creosote", a petroleum based preservative.  This is what gives cross ties their distinctive  aroma.  The drainage is to prevent washouts and standing water.  Diesel-electric locomotives are designed to travel on inundated rail, but with a water level no more than 4" above the top of the rail.

True enough, ballast serves as a good base under the cross ties and the rail.  But it does something else.  The forces that run through the train's draft gear (couplers between cars and the "center sill" under the length of each car) ultimately dissipate where wheel meets rail, as well as the weight of each car.  These days, a freight car weighing 138 tons is not out of the ordinary and, in fact, the norm.  The forces encountered where wheel meets rail and their interaction are called "Track Train Dynamics"  (has nothing to do with dynamic brakes on a locomotive).

The ballast, while strong enough to support the track structure and the traffic that passes over it, also has an amount of "give" to it (never where "gage" is concerned).  Then next time you are observing a train pass by, look what happens to the rail as each car's wheels pass over it.  You will see the rail "pumping", or flexing, up and down.

This helps dissipate the forces you see exhibited as each car passes over, the same way some highway guard rails and race track guard rails are designed to dissipate the forces associated with collisions.

In addition, the ballast helps the rail stay in place, with temperature extremes that cause the rail, almost all of which is welded together to form CWR "Continuous Welded Rail" where pieces of ribbon rail are welded to gether to form long stretches of track without the "joints" (no, not that kind of joint) that used to produce the "clickety-clack" of the wheels passing over it.  As a continuous piece, there are no joints to allow for expansion in hot wheather or contraction in cold weather.  The ballast has a little give here, too.  But the tendency of the rail to expand lengthwise is held in check by devices known as "creepers."

In addition, ballast is composed of different types of rock in different sizes, from the red of pumice to river rock or crushed granite.

So, the answer is, ballast provides for drainage, track structure support, track train dynamics and keeping a lid on effects of extreme temperature change.

Answer 3

so the track doesn't move and can handle the weight of the train

Answer 4

because it's cheaper than putting soil

Answer 5

So when it rains the dirt doesnt get all muddy and then the Tracks sink in.

Answer 6

Wow great answer hoghead! You work in MofW?

Answer 7

easy drainage,and its called ballast,it locks the track together,and when trains go over it,it evenly distributes the load along the track.in summer when its really hot the possiblility of a misalignment can be increased if there is insufficient ballst the shoulder which is the outside,this mainly happens on curves,but is known on straight track also.if you want more info on the formation of a railway track just email me if you are that interested.