TRIVIA: Longest time at same same speed

[Rob F]

What is the longest TIME that a scheduled passenger service can run at the same speed in the UK?

I am not talking about the longest stretch of track at the same speed (e.g. 20 miles at 100mph would take less time than 10 miles at 40 mph) or about long lengths of constant speed rated track where station stops are required.

There has to be a scheduled train for it to count, and the train has to be running at full line speed.

 

[Peter Mugridge]

I would expect that to be any of the King's Cross to York non-stop services?

 

[sjm77]

Please can you clarify whether it is 'constant speed' or 'full line speed'. If it is the former then Kings Cross to York would not count becuase of course there are numerous speed restrictions (Holme Fen, Peterborough, Stoke Tunnel, curve at Grantham etc etc).
For a train to run at a constant speed then you need a long stretch of uniform line speed but not too fast becuase it will end too quickly!

I will offer a contender;
The 1336 Carlisle to Leeds is first stop Appleby. From Petteril Bridge Jcn in Carlisle the speed limit is a constant 60 mph all the way. This train has the ability to run at 60mph exactly for ~30 minutes.

*There is ~49 miles of 125 mph EPS on the WCML between Kings Langley and Weedon (approximately). Of course this would only take a Pendo' 24 minutes so not as not as long time wise.

 

[Rob F]

I meant constant speed, but that speed should also be full line speed, so your S&C example works very well.