How are rails bent to form curves in rail lines?

Question

How are rails bent to form curves in rail lines?

Answer 1

the rails are flexable, to an extent.  none of the curves in a railraod track are  very sharp.  the curves are long and sweeping.  its a little bit of bend spread over a long distance.

any long pieces of steel, whether rail or pipe, or beams  will give or "bend".  if you lay a long piece of steel on the ground and have one end fixed,  the loose end will move side to side fairly easily, depending upon how big the piece is.

on a railroad, they lay the crossties first, forming the curve.  attach the rail on one end, and the other end can be pushed over  side to side to follow the crossties.

Answer 2

It's not really much of an issue. The curves are so slight relatively speaking that as the rail is spiked to one tie, it is only a matter of a slight movement and it is in line wiht the next tie plate. It is not really "bent" so much as simply flexed from one tie to the next.

Answer 3

Being a signaller in the UK, I have spoken to the guys that actually lay the track. They tell me that rail comes in standard 60 ft lengths here. To lay a long sweeping curve, there is a degree of flexibility in the track. For a sharper curve, the rail is cut smaller and fishplated. (Held together by large pieces of metal and bolts) in order to gain the sharper curve.

Anyone who says that curved rail is made curved before being layed is not telling the truth. (In the UK at least)

The curve takes place during the laying of the track and heat is NOT used.

Answer 4

Again, Osto is right. Rails are more flexible than you think. They can be formed to fit a curvature as they're being spiked down. In the case of a kink in the rail, that can be straightened with a device that is similar to a horizontal hydraulic jack, that grips the rail and applies lateral pressure. A good example of a kink is if you look closely at this avatar.

Answer 5

extreme heat does help form the cuirves which make bending the track much easier as well.

Answer 6

Today with rail being welded (sometimes known as ribbon rail) and I believe it comes in something like quarter or half-mile lengths, railroads simply mold the pliable rail to whatever the curvature may be.  Years ago when rail came in standard 39 foot lengths, I believe, the rail manufacturers (steel mills) would prefab rail to different curvatures (and yes, heat is always applied when actually laying the rail).

Answer 7

osto is right, Gandy dancers use johnson bars to align the rail once the ties are laid. No heat is EVER applied to the rail as it would take the temper out of the riding surface.