Guidance on Forming Curves Using Mild Steel Bar Rail

When using mild steel black bar as a rail, curves can be formed successfully with some care.

Forming curves using mild steel bar rail

For large radius curves down to around 40 feet (12.2 metres), it is usually possible to bend the bar rail on site. This can be done by hammering stakes into the ground along the desired curve and carefully working the rail into shape. Even 12 × 30 mm bar can be formed this way with patience.

For tighter radii, it can be done with care, but we generally recommend pre-rolling the rail by a local engineering company to ensure accuracy and reduce stress.

Once curved, it is essential that:

• The rail is firmly bottomed in the chair

• Ballast is packed correctly and is supporting the track

• Strong angle iron fishplates or similar restraints are fitted to hold the curve in place

Please note that if an unrolled curved section is later dismantled, stored tension in the rail will be released, so care should be taken.

Gauge widening

On tight curves, gauge widening may be required. This can be achieved either by using our complete rail-and-chair system or by jig-drilling sleepers to the required gauge.

Track use and maintenance

The railhead, not the sleepers, should carry all loads on bar rail track. If walking along the track, weight should be placed on the rail rather than directly on the sleepers.

Because the bar rail has no profile for the chair to lock into, loose sleepers can allow chairs to slide along the rail slowly. This can create gaps that could fill with debris. Regular inspection is essential. Any dropped sleepers or chairs should be lifted, debris cleared from under the rail, and the sleeper firmly packed back to the correct height so the bar rail is fully bottomed in the chair.