Slow zone

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Dual PSR on the 125 mph Midland Main Line at Belper
Temporary speed limit before a flange lubricator at Belper

A slow zone, in America, is an area where a train is forced to slow down for either structural, construction, power, signal, or track problems. Slow zones limit a train to about 10-35 MPH. Notification to train crews is referred to as a "slow order."

United Kingdom[edit]

In the United Kingdom the term "speed restriction" is used, either permanent (PSR), temporary (TSR) or emergency (ESR).

TSR and ESR[edit]

TSRs and ESRs are used where movement of the track is causing problems.

PSR[edit]

PSRs are usually only for curves or switches and crossings. PSRs may also be imposed where signal spacing is short relative to braking distances.

Dual PSR[edit]

As will be seen from the image, some PSRs are dual, allowing certain trains to pass at a higher speed, such as InterCity 125 (HST) and certain other classes.

See also[edit]

References[edit]