Tracksure - Nut Locking Device

Tracksure has used innovative technology to develop a patented nut locking device that prevents nuts from self-loosening as a result of vibration. Tracksure’s device offers a significant reduction in labour-intensive track maintenance, whilst providing a cost-effective safety benefit to operators, the public and those responsible for track maintenance.

NUT LOOSENING

Huge stresses and strains, caused as locomotives pass over bolted joints, lead to vibration and settlement. Both vibration and settlement are causes of nut self-loosening. Joints such as points, turnouts, crossings, temporary clamps and fish plates are subject to immense stress and are liable to loosen and settle.

This has huge implications for safety and places a significant onus on labour-intensive maintenance. Whilst stringent track maintenance and nut torquing regimes are essential, the sheer number of joints to be maintained makes this an extremely difficult task.

For those companies and organisations charged with track maintenance, both the costs and the management time involved are burdensome. However, incidents such as Potters Bar and the recent derailment in Cumbria show the potentially devastating results of nuts coming loose, whatever the cause.

PATENTED NUT LOCKING DEVICE

Tracksure has developed a patented nut locking device that prevents nuts self-loosening through vibration. The innovative technology behind this product is both ingenious and simple, and it can be used with many different track and rolling stock applications including crossings, temporary joints, turnouts, rail clamps and insulated joints, buffers, and brake systems.

WS Group holds worldwide patents for the device.

KEEPING NUTS SECURE FROM LOOSENING

Tracksure’s device comprises of three components: a modified bolt with a reverse thread, a locking nut and a serrated locking cap. The modified bolt is fitted and the nut added and torqued in the standard manner. The Tracksure locking nut is then tightened on the reverse thread, against the first nut, using a conventional wrench. The chrome serrated locking cap is then pushed fully down over both components, and a spring clip clicks it into place. The locking cap will automatically tighten against the original nut should it start to loosen even microscopically, locking it firmly in place and maintaining a secure fixing.

CASE STUDY: BRAKING SYSTEM INSTALLATION, ROTTERDAM

The specific purpose of the brake system is to allow for the automated management of freight wagons in marshalling yards. The everyday maintenance of these brake systems is manpower-intensive and the replacement of standard joints is time-consuming and difficult. The job is hugely significant when multiplied by the sheer number of braking systems.

Tracksure’s devices have been fitted by ProRail to an automated braking system in a marshalling yard in Rotterdam. As part of regular maintenance in this yard, existing bolts have to be removed. In this installation they were then replaced with the Tracksure locking device. The aim of the trial is to evaluate the improvements to both the security of joints and the cost-effectiveness of the maintenance regime.

This installation has been in place for over five months (as of April 2007) and there has been no movement at all in the Tracksure joints. Further applications have now been commissioned by Pro Rail with temporary clamps and fish plates.

INDEPENDENT VIBRATION TESTING

Independent vibration testing has been carried out on the device by Bolt Science. A Junkers machine was used to carry out 13 tests, both with and without the device fitted, to establish the efficacy of its locking performance relative to a standard free spinning nut. The average retained clamp force of a standard nut was 21% whereas the average retained clamp force with the device fitted was 95%.

AWARD-WINNING DESIGN

Tracksure’s device was winner of the Rail-Tech® Europe 2007 Innovation Award in March 2007. The award was presented to Tracksure for being the most ‘innovative product with significant market potential’.