PSR

[PJW]

As something else to think about, what is the difference between an ESR and a TSR (E == emergency, T == temporary).

The TSR should not come as a surprise to the driver; it will already have been published via the Weekly Operating Notice or at least posted in the Late Notice case at the signing-on points. Generally they are pre-planned, perhaps following some P'Way relaying with the line reopened but not yet at its full speed. Sometimes as a response to an assessment of the gradually deteriorating state of the track, embankment, structure etc.

The ESR is an ugent response to something pretty serious that has just happened / been noticed; tend to be of short physical length but of extremely low speed, perhaps due to a specific rail defect. Because they will be otherwiise unexpected, drivers should wherever possible be warned prior and a black / yellow chevroned marker board with flashing high intensity flashing lights are placed on the approach.

Due to therir nature ESRs are generally targetted for extremely rapid rectification. Some TSRs were actually in practice long-term, particularly those imposed due to infrastructure deterioration which was limited and the effect on traffic insufficient to justify big expenditure to resolve. There were a huge number of TSRs imposed after the Hatfield accident and the scale of the remedial work needed nationally meant that resolving them was a slow process. The rules now are that TSRs should not be in force for more than a year; the effect of this is that some long term TSRs have been converted into PSRs- this of course means incorporation into the Sectional Appendix, modifying the speed signage of the route etc.

Also, which is more [sic] risky and why?

I think this is a bit of a Mod1 question for a student to attempt!