Why stones along the railway track?

Question

if they are for a firm footing for the tracks why are they loose???

Answer 1

It's called ballast and it helps keep the ties (sleepers) in place and also provide drainage.

Answer 2

They form the bed that the rails lie on.

Answer 3

drainage

Answer 4

The rocks under the tracks are called ballast, and are there to provide a firm footing for the ties and the track.

Answer 5

The ballast is a perfect medium as a multi-tasker.

It provides for drainage, provides a secure foundation for cross ties and rails while allowing "give" for weight of engines and cars above to lessen the forces where wheel meets rail (aka track-train dynamics), helps with weed control and allows for limited expansion and contraction of track structure during high temperatures and low temperatures.

It is durable, relatively inexpensive, easily transported, readily available and easy to replace or shape.  On older stretches of track, the ballast was not stone but cinders, volcanic in origin and usually handy to where the rail bed was constructed where used.  Cinders are easily recognizable due to their reddish color.

Addendum:  They may appear loose on the top, but they all mesh together in what in an engineering term is "consolidation".  This is why, when the ballast is disturbed due to replacement of ties or the ballast itself, there is always a temporary speed restriction over the affected length of track at a speed of 10 MPH, usually for a week or more, for consolidation to occur, before returning to normal track speed.

Answer 6

They are ballast the stones are there for drainage and to keep weeds from growing around the tracks to help keep fires from the trains wheel sparks

Answer 7

they are loose so that they can settle down when the vibrations are produced by running trains!