Strainstall systems monitor a complex array of parameters in the dynamic and often critical functions of rail tracks, bridges, rolling stock, components and geotechnical engineering. Working closely with the rail industry has provided Strainstall the opportunity to develop a number of specialist systems to help safeguard rail infrastructure.
From the supply of a load pin for railway points monitoring to a complete assessment of actual and potential stresses on railway track, Strainstall’s unique expertise is fully focused on providing realistic and reliable solutions for enhancing safety and performance.
Our clients include Network Rail, Eurotunnel, London Underground, SMRT, Balfour Beatty, AMEC, Amey, Mott MacDonald, Corus Rail, Nuttall, May Gurney and Vialis, as well as rolling stock manufacturers such as Bombardier, Alstom and rail asset condition monitoring companies.
Railway points force monitoring
Strainstall holds the patent for the widely used ‘Points Pin’. This force-measuring pin replaces a component within railway points to monitor the force required to operate. The remotely monitored information provides data for an enhanced preventative maintenance programme or even impending failure.
WHEEL IMPACT LOAD DETECTION (WILD)
Wild is a trackside asset protection system that has been specifically designed where wheel impact diagnosis is required to individual wheel level. Sensors are mounted directly onto the rails, and each time a train passes the system records data.
A number of wheel defects are detected including pitting, circumferential cracking, out of roundness and wheel flats. Any wheel that generates a force that is above a pre-defined threshold causes alarms to be triggered and a report identifies the particular wheel that needs further investigation.
Railway bridge monitoring systems
Strainstall has carried out work on hundreds of bridge structures, ranging in scale from the Forth and Tay Bridges, Royal Albert Bridge and Newcastle High Level Bridge to metro span underbridges.
Our comprehensive service not only deals with instrumentation and monitoring, but also provides access to the information that is really needed about a particular structure. We can provide instrumentation for use during repair or strengthening operations, which can include displacement and strain measurement equipment, and are also able to assist in devising suitable tests or monitoring for problem structures.
The information that can be delivered includes comprehensive load test data, in situ dead load stresses and ongoing structural health monitoring.
Embankment monitoring
Railway lines that run alongside embankments and cutting slopes which are prone to landslips are often subject to temporary speed restrictions, causing delays.
Strainstall has designed an embankment monitoring system that provides warnings in the event that the ground moves or conditions change such that movement could happen. Various sensors are fitting in the location of potential slip circles to detect creep movements, ground water levels and ground movement.
IN SITU DEAD LOAD STRESS DETERMINATION
Before the carrying capacity of a bridge can be properly assessed, the dead load stress conditions need to be known. This can be particularly important for post-tensioned concrete bridges. Strainstall have devised a number of techniques for the measurement of in-situ dead load stresses.
Rockfall monitoring
Trains that run on railway lines that pass a rock slope or cliff face can be at risk from falling rocks, with speed restrictions imposed as a result. Strainstall can supply rockfall monitoring systems that alert signallers when rockfall has occurred, allowing them to take appropriate actions.
Such a system enables temporary speed restrictions or line closure to be imposed only when there is a measurable risk to trains, as opposed to blanket restrictions.
Bridge scour monitoring
Bridge scour has been identified as one of the three main causes of bridge failure, and it is estimated that it accounts for 60% of all bridge failures. Strainstall has designed a bridge scour monitoring system specifically to warn bridge operators when scour monitoring has occurred.
When sensors detect that erosion has taken place a warning message is sent, enabling inspectors to take appropriate action, such as closing the bridge until it can be physically examined.
Flood monitoring
Strainstall’s flood monitoring system has been designed for rail bridges that frequently experience flash flooding. At these bridges, once the water level has risen to a certain limit they have to be closed to traffic for both operational and safety reasons.
By monitoring water levels and predicting when the bridge closure levels will be reached, the train movements can be managed more effectively. Not only can bridges be closed and reopened in a timely manner, but decisions can be made about whether to allow trains to pass sites where the water level is rising, so as to avoid them becoming stranded on the wrong side of the bridge.
Vehicle and rolling stock monitoring
Strainstall regularly install strain gauges and other sensors on rolling stock components to carry out dynamic monitoring. The information obtained can be used in fatigue analysis.
Permanent and temporary monitoring systems have been developed for measurement of ride characteristics, vibration and wheel/track interaction effects. These have been provided for major train manufacturers for use in the UK and worldwide.
