On the left is the profile of this squat switch rail.

There was a clicking sound as their elevator cage switched rails.

The switch rails may be moved left or right, under the control of the signalling system, to determine which path the train will follow.

The higher baseplate also supports the switch rail better.

At the junctions of train tracks, the gap in the frog or switch rail is wide.

Manufacture of the switch rails was a complex process, and that of the crossings even more so.

The cause was a worn switch rail and an imbalance in wheel loads across the leading carriage of the train.

A turntable-like device which allows wagons to switch rails: Turntable (rail).

The centre diagram shows how the switch rail has to be planed, and on the right it is shown fitting against the stock rail.

The points move over a lubricated slide chair which ensures that the switch rails move freely when operated.

Laid similar to normal track, a point typically consists of a frog (common crossing), check rails and two switch rails.

The accident occurred near Purley Station in Surrey, when one train ran into the other as it was switching rails.

A single tongue trap consists of only one switch rail, leading away from the main line to a short tongue of rail.

Many older s&c units had a loose joint at the heel so that the switch rail could turn to close to the stock rail or open from it.

The points (switch rails or point blades) are the movable rails which guide the wheels towards either the straight or the diverging track.

When the switch rail was closed a reasonable alignment was secured; when it was open, no wheel could run on it so it did not matter.

The tangential switch rail has less steel planed away, and the mid part of the switch "scallops" into the web of the stock rail for greater strength.

If the switch rail does not close up tightly to the stock rail, the facing point lock cannot be engaged and only a small tolerance of less than 3mm is permitted.

As speeds rose this was no longer feasible and the switch rails were fixed at the heel end, and their flexibility enabled the toe end to open and close.

The faulty points meant that the switching rail moved under the weight of the Virgin Pendolino and the wheels on the lead coach slid between the lines, derailing the train.

At faster speeds on the turnout road, the divergence from the main route is much more gradual, and therefore a very considerable length of planning of the switch rail is required.

The switch consists of the pair of linked tapering rails, known as points (switch rails or point blades), lying between the diverging outer rails (the stock rails).

To ensure a good contact a small tab is bonded to the underside of each switch rail which makes a rubbing contact with the underside of it's corresponding stock rail.

Olgierd Mikosza, the inventor of the system, claims that switching rails at intersections will be done at full speed of about 50 km/h, with a minimum spacing of 10 m.

Trouble was experienced with the mixed gauge points, and some were converted to a type where the approach rails were shifted to meet the lead rails, so that there were no switch rails at all.