Biggest SP differential (SP -- higher speeds allowed for Sprinters and the like)

[Rob F]

Are there any SP differentials anywhere bigger than this on the Robin Hood Line:

Wighay Road crossing

A differential of 55mph seems quite a lot!

 

[4F89]

Sprinter specific, or all normal diffs?

 

[The Planner]

Probably lots that aren't specifically signed and are instructions in the sectional appendix. Good few on the Cambrian, 30/130kmh near Westbury, 15/90kmh at Caersws, a few 15/95kmh at Dovey

 

[61653 HTAFC]

Paddock viaduct just outside Huddersfield on the line to Sheffield is 10/MU 55 if I'm remembering right- I might be out slightly on the MU speed but can't go and check for now!

 

[High Dyke]

Paddock viaduct just outside Huddersfield on the line to Sheffield is 10/MU 55 if I'm remembering right- I might be out slightly on the MU speed but can't go and check for now!

Not far out with the MU speed. It's shown as 50mph.

There's one on the Skegness line at one of the ABCL (Automatic Barrier Crossing. Locally monitored by train crew.) where Classes 4,6,7,8 are shown as 15 mph in one direction, but 20 mph in the opposite. Passenger trains can travel at 30mph and 40mph respectively. The restriction is for the distance between level crossing speed signs and the crossing itself.

 

[CyrusWuff]

Not signed on the ground, but mentioned in the Sectional Appendix, is a limit of 5mph for Class 37s (down from 30/50 and 30/65) between 202 miles 21 chains and the 202 milepost on the Chiltern Down Main past Willesden Green station. It's possibly due to the radius of the curves where the main line goes "round the back" of the LU station, but that's purely a guess on my part.

 

[TheEdge]

Lots of sections of the East Suffolk are 20/55.

 

[Wilts Wanderer]

For years there has been a gauging restriction at Dundas Aqueduct between Freshford and Bathampton of 30/60 (SP70).

 

[_toommm_]

Wasn't there a 20/60 which affected locomotive hauled trains between Norwich and Brundall Gardens?

 

[Deepgreen]

Numerous places where specific steam locos are heavily restricted - e.g. Brookwood station down platform 10mph for some locos vs. EMUs at 90!

 

[AlbertBeale]

What's an SP differential?

 

[4F89]

What's an SP differential?

Sprinter

 

[Philip Phlopp]

What's an SP differential?

It's a (normally) higher speed limit for any unit that is grouped under the "Sprinter" family - it was initially just Sprinters, then Super Sprinters and Express Sprinters came along, and now there's all sorts of other DMUs included (but not the Siemens Class 185 units). The ability to run at higher speeds is due to the lower axle weight (compared with a locomotive) and superior braking performance that enables such units to run at higher speeds without damaging/excessively wearing the permanent way, and to have an acceptable braking curve when running at that higher speed.

 

[AlbertBeale]

Sprinter

Ah - thanks. But why would the speed limit for those trains be so much less restrictive than for anything else?

EDIT - just seen the second response to my original question, which largely answers this point. So thanks for that. Though I am surprised that the difference in the allowed speed is so great.

 

[hexagon789]

Wasn't there a 20/60 which affected locomotive hauled trains between Norwich and Brundall Gardens?

Yes, I think it's still there, for a bridge iirc

 

[Class 170101]

Wasn't there a 20/60 which affected locomotive hauled trains between Norwich and Brundall Gardens?

Yes, I think it's still there, for a bridge iirc

Definitely still there.