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Old 16th February 2018, 09:26
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Beeyar Wunby Beeyar Wunby is offline  
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Join Date: Dec 2012
Location: NW Norfolk
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Quote:
Originally Posted by swisstrains
On the railways you often see differential temporary speed restriction signs like this one.
http://www.railsigns.co.uk/pics/pic_tsrwb2/pic_tsrwb2.htmlThe slower speed appears to apply mainly to freight trains but what actually determines which speed applies to which type of train?
Can anyone throw some light on the subject please?
Coming to this a bit late, but here's a bit of meat.

Differential boards can also apply to Permissible Speeds (what most of know as linespeed - before NR muddied the water) as well as Temporary (TSR) & Emergency (ESR) speed restrictions.

The signs section of the rulebook (linky here...UK Rulebook) deals with it if you want some late night reading. What we want currently hides on page 802

"Differential temporary speed restrictions

A temporary speed restriction can show different speeds which apply to different types of trains. The bottom figure always indicates the higher speed. It applies to:

passenger trains (loaded or empty)

parcels or postal trains (loaded or empty)

light locomotives.

The top figure applies to all other trains"

Most ESRs, and many TSRs are imposed because of track condition, so the speed is set to allow trains to keep running until the P-Way women & men (god bless 'em) can get out and fix it.

We get some quite hefty differential ESRs on the ECML, such as 30/100 on a Permissible Speed of 125mph. This is usually for the condition of the track or crossings. Passenger trains usually weigh between 20-40 tons per coach (though I stand to be corrected), whereas some of the sand/aggregate trains can weigh up to 100 tons per hopper. You wouldn't want that monster hammering over a weak rail at 60MPH.

BW

Last edited by Beeyar Wunby; 16th February 2018 at 09:29.
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