In joining of two pieces of railway line which technique is used(like welding,coupling or joint)?

Question

joining process

Answer 1

nowadays welding is the most common , bec, the impact of the joint over the train rolling resistance is higher than welding

Answer 2

The latest technology is "Thermite welding". In this technology iron powder in presence of Aluminium in oxide form is ignited. This results in sudden temperature rise to about 4500 degree Centigrade. This temperature melts the steel and joining is done.

If you look to 9/11 twin tower tapes available on youtube.com , you will find melted steel pouring out of windows. It is only because of lot of steel and aluminium compound was ignited by plane petrol and the temperature reached to 4500 degree centigrade melting the steel of twin towers. The twin towers were made of mainly steel. Presence of "Sulphur" further reduces the time of reaching this temperature. It is very surprising that in twin towers residue , sulphur is present. -- PRANCHAL

Answer 3

Two methods are now common. Thermite can be used for quick joins or they have specialised cars that produce flash butt welding. These use hydraulic cylinders to position the joint, heat the ends with high current, then weld by displacing the rail inwards. Upset is ground away. Rails only joined at several kilometre lengths  (although there are places in the world still using fishplates and spikes).

Answer 4

They have expansion joints because of large ambient temp changes.

Answer 5

Older railway lines used fishplates but modern ones use continuous rails and welding on concrete sleepers.

At least they do in the UK.

The welding is done by Thermite welding.

The rails are welded at mean ambient temperature and become stressed at low and high temperature.

Answer 6

as i have seen practically joining the line, i don't know the name of the exact process but it can be said "brick die casting"  in this the ready made brick dies of rails shape are made, taken to that location and they pore molten metal and break the brick die; u get the joint or it might also be called thermit welding