line speeds

[whole diary]

[6 OF 2 redundant adjunct of unimatrix 01]

I was driving along the a30 lastnight when I noticed a train Exeter bound and was struggling to keep up at legal speeds? Was between Exeter and honiton

[devon_metro]

More than 70mph then wasn't it 

[6 OF 2 redundant adjunct of unimatrix 01]

yeh but seriously anyone know

[Chris from Nailsea]

According to Network Rail, 80 to 105 mph.

See figure 4 on page 8, at http://www.networkrail.co.uk/browse%20documents/StrategicBusinessPlan/RoutePlans/2008/Route%204%20-%20Wessex%20Routes.pdf

So yes, rather faster than Citylink, relex109! 

[6 OF 2 redundant adjunct of unimatrix 01]

thats quite a high speed for that line isnt it! i mean the distance between honiton and feniton is nothing so why 90?

[Btline]

90 is the highest speed of the 158s.

Why run any slower? Do you want extended journey times? (and that route is slow enough!)

[6 OF 2 redundant adjunct of unimatrix 01]

90 is the highest speed of the 158s.

Why run any slower? Do you want extended journey times? (and that route is slow enough!)

well its a class 159  and yes 90 is the highest speed of these units but i didnt think the speed of the LINE was 80-105 for a single line in that area that quite impressive! the line between weymouth and  c c is only 40-80

[The Grecian]

The line between Salisbury and Exeter has a general limit of 85mph with few restrictions (90mph Salisbury-Worting Junction and 100mph onto London). This is largely because it was built as a main line to rival the Paddington route, so it's fairly straight and none of the gradients are steeper than 1 in 80. The Weymouth - Castle Cary route was also built as a main line (Weymouth-Westbury-Swindon-Paddington) and so that's also fairly straight. That's presumably maintained to a lower standard as the general limit between Dorchester and Castle Cary is 75mph, although it's 40mph between Yeovil Pen Mill and Yetminster, while there's a 15mph through the passing loops at Dorchester, Maiden Newton and Yeovil.

I don't work for the railways BTW^▸ (by the way) - I just like to know how fast I'm going as a passenger!

[Btline]

Very interesting, thanks.

I, too, like to know speed limits on routes I travel on.

Do SWT^▸ (South West Trains) reach 100 mph much around London? Those Waterloo lines are quite congested are they not?

[G.Uard]

Very interesting, thanks.

I, too, like to know speed limits on routes I travel on.

Do SWT^▸ (South West Trains) reach 100 mph much around London? Those Waterloo lines are quite congested are they not?

In the lead up to electrification of the SW Main Line back in the mid 60s, the Bullied Pacifics, particularly the Merchant Navys regularly achieved 100mph plus between west of London and Southampton.  The high HP electric REP/TC^‡(resolve) combos were timed at 100mph as were the Wessex Express trains which superseded them.  Things are less breathtaking on the West of England line after leaving Basingstoke, but the 159s, (a modification of the 158 with a slightly different braking system, which means that these units will not run in multiple with other 'sprinter' types), easily cope with the 90mph max line speeds.

[smithy]

Very interesting, thanks.

I, too, like to know speed limits on routes I travel on.

Do SWT^▸ (South West Trains) reach 100 mph much around London? Those Waterloo lines are quite congested are they not?

In the lead up to electrification of the SW Main Line back in the mid 60s, the Bullied Pacifics, particularly the Merchant Navys regularly achieved 100mph plus between west of London and Southampton.  The high HP electric REP/TC^‡(resolve) combos were timed at 100mph as were the Wessex Express trains which superseded them.  Things are less breathtaking on the West of England line after leaving Basingstoke, but the 159s, (a modification of the 158 with a slightly different braking system, which means that these units will not run in multiple with other 'sprinter' types), easily cope with the 90mph max line speeds.

they can run in multiple with other sprinters,i remember a case last year when an fgw 158 en route back from ports had problems so fgw hired a 159 to couple up and box the defective cab in to get back to bristol.also in wessex days a 159 coupled to a stranded 153 at warminster to get it in to the bay at salisbury to get looked at by fitters.

[The Grecian]

I think the fast lines in the middle are 100mph from Worting Junction to Wimbledon with 90mph on the outer slow lines. I'd assume that the electric Desiros on fast Bournemouth services can still reach and maintain 100mph without difficulty. The Surbiton/Wimbledon area is where things start to get really busy. I don't often travel in that area though, so I could be wrong.

[Timmer]

Welcome to the forum The Grecian

[Btline]

I think the fast lines in the middle are 100mph from Worting Junction to Wimbledon with 90mph on the outer slow lines. I'd assume that the electric Desiros on fast Bournemouth services can still reach and maintain 100mph without difficulty. The Surbiton/Wimbledon area is where things start to get really busy. I don't often travel in that area though, so I could be wrong.

Thanks. It would be interesting to look at 1960s timetables from places like Woking and Surbiton into Waterloo, and see whether the journey times are longer today. I assume that there are many more (peak) services now.

[Electric train]

I think the fast lines in the middle are 100mph from Worting Junction to Wimbledon with 90mph on the outer slow lines. I'd assume that the electric Desiros on fast Bournemouth services can still reach and maintain 100mph without difficulty. The Surbiton/Wimbledon area is where things start to get really busy. I don't often travel in that area though, so I could be wrong.

The third rail in London is nominally at 660V this is to make it compatible with LUL^▸ (London Underground Ltd), where as out side the London area it is nominally 750V.

There are plans to raise the London area nominal conductor rail voltage to 750V this mainly to improve power supply capacity, not to increase train speed, without adding as many substation if the voltage were to remain at 660V, there has to be some interfacing and separation between LU and NR^» (Network Rail - home page), all of which is a complex task covering a few hundred transform rectifier units.

There is an upper limit of about 100 MPH for a 750V conductor rail system due to reliability of shoe contact and the amount of power that can be drawn from the system more substations could be added but that comes down to the cost / benefit equation to increase speed by 25% would mean 4 times as many substations