It is important that the risk from earthwork collapse following extreme rainfall is managed. But, implementing speed restrictions throughout the whole part of the network can also cause increased journey times, increased risk of SPADs, and needless delays to many other journeys.

In addition to the stress and operational challenges this creates for asset managers, route controllers, signallers, drivers, and passengers, this can also create very significant revenue costs and financial penalties. Blanket speed restrictions may be well-intentioned, but they can cause far more problems than they solve.

What is PRIMA?

PRIMA is short for Proportionate Risk response to Implementing Mitigating speeds to Assets. It is an operational planning tool that evaluates safety risk, economic impact, and drivability of proposed speed restrictions.

Its use will ensure that rail’s response to extreme rainfall is proportionate. It evaluates three types of risk: derailment risk, speed of restriction risk, and economic impacts. By including all three types of risk in its calculations, PRIMA provides a more effective operational plan than blanket speed restrictions. PRIMA can also be used before extreme rainfall occurs so different parts of the network are prepared for possible risks in advance.

PRIMA is currently being piloted on North West and Central region. This will inform the nationwide roll-out with Network Rail.

Learn more about PRIMA, watch our short video.