Table of Contents
Why do rails need ballast?
Track ballast forms the trackbed upon which railroad ties (sleepers) are laid. It is used to bear the load from the railroad ties, to facilitate drainage of water, and also to keep down vegetation that might interfere with the track structure. Ballast also holds the track in place as the trains roll over it.
What is the advantage of ballasted bridges?
PROS: The resilience provided by the ballast, the possibility of track realignment, effective drainage and low initial construction cost are all attractive features of ballasted systems.
What is the disadvantage of ballasted bridges?
Ballasted track is easy to be deformed. Ballasted bed requires frequent and costly maintenance. Train speed is limited on the ballasted track. Ballasted track has poor life expectation (about 15-20yrs).
Is it possible to have a ballastless track?
Ballastless tracks therefore offer a high consistency in track geometry, the adjusting of which is not possible after the concreting of the superstructure. Therefore, ballastless tracks must be concreted within a tolerance of 0.5 millimetres (0.0197 in).
What do you call a railroad bridge?
A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide valley, road, river, or other low-lying terrain features and obstacles.
What is BLT in railway?
Sub: New design of Ballastless Track (BLT) for use on Indian Railways. A new design of Ballastless Track with Indian Fastening System (BLT-IFS) has. been developed by RDSO and approved by Railway Board (ME) for the purpose of trial. on Zonal Railways.
Why are ballast less railways used in tunnels?
Advantages of ballastless track Stabirail’s fast-working railway construction train is operated by a modern 3D system, which allows for accuracy within a 2mm range. Ballastless track can be constructed at a lower height, which is advantageous in tunnels where headroom is limited, and also creates a reduced dead load.
Why is concrete used in railway tracks?
1. The stones don’t allow vegetation to grow on railway tracks which could weaken the ground on which the railway lines run. 2. Track ballast also keeps water from reaching the track on a regular basis and softening the ground.
What grade of steel is railroad track?
So what kind of steel are railroad tracks made of? Railroad track steel is typically 1084 or equivalent hot rolled steel. This is a medium carbon steel with 0.7\% to 0.8\% carbon and 0.7\% to 1\% manganese. This type of steel is great for heat treating.
Do bridges have to be built with ballast?
Thousands of bridges are built without ballast or a concrete slab. Elevated railroads, like those in New York, Brooklyn, or Chicago, are built on steel girders or trusses, the ties fastened with bolts to the steelwork. Most railroad bridges are built the same way, even bridges miles long.
What is a ballast-less track?
In a ballast-less track, used in Metro System, the ballast is replaced by bed of concrete. On the concrete bed, concrete sleepers are laid. There on rails are secured by use of rubber-pads and fastenings. The ballast-less track has longer life – more than 60 years.
What is the purpose of ballast beneath the rails?
Ballast beneath the rails provides cushion to the impact of train movement and keeps the track geometry stable. It reduces wear and tear of rails.
Why doesn’t Delhi Metro use ballast under its tracks?
Delhi metro need not to use ballast as its short distance, in tunnels or over bridges in controlled ground conditions thus the tracks can be more conveniently cemented. And jai parimi in the other answer has a point too. Ballast beneath the rails provides cushion to the impact of train movement and keeps the track geometry stable.