Why there is no stones in metro railway track?

Answer 1

The stone in old railways track arebasically "track ballast".itis packed between, below, and around the ties.

It is used to facilitate

drainageof water, to bear the load from the railroad ties, and also to keep down

vegetationthat might interfere with the track structure.

This also serves to hold the track in place as the trains roll by. It is typically made of

crushed stone, although ballast has sometimes consisted of other, less suitable materials. The term "

ballast" comes from a nautical term for the stones used to stabilize a ship

A good ballast should be strong, hard-wearing, stable,

drain-able

easy to clean, workable, resistant to deformation, easily available, and reasonably cheap to purchase.

Early railway engineers did not understand the importance of quality track ballast

they would use cheap and easily-available materials such as ashes, chalk, clay,

earth, and even

cindersfrom locomotive fireboxes.

It was soon clear that good-quality ballast made of

rockwas necessary if there were to be a good foundation.

The metro railways use the most modern technology which involvesballast-less track system therefore there are no stones to be seen in the tracks.

RHEDA 2000 is a latest ballast-less track system.

Please reffer the links below for more information

http://www.railone.in/fileadmin/dateien/03 Broschueren/EN/Rheda2000 EN 2011 ebook.pdf

http://www.railone.de/uploads/pics/OhneBewaehrung_EN_02.jpg