Tube trains speed

[The0]

With limiters off can an s stock reach over 60mph or can it's motors actually not go over 60

== Doublepost prevention - post automatically merged: 25 Jul 2023 ==

Also what's the slowest speed on the tube and were is it?

 

[Dstock7080]

S Stock are designed to operate at 100kph (62mph) in CBTC, although this is temporarily been reduced to 90kph (56mph) while a tag reading issue is resolved.

Most depots have a 5mph limit and there will be temporary 5/9/10mph limits for infrastructure issues somewhere around the system.

 

[Railperf]

With limiters off can an s stock reach over 60mph or can it's motors actually not go over 60

== Doublepost prevention - post automatically merged: 25 Jul 2023 ==

Also what's the slowest speed on the tube and were is it?

in manual driving mode S Stock can reach 62mph - though the acceleration rate is far slower than CBTC and you need long distance between station stops and downhill run to achieve it.
20mph seems to be the lowest running speed on tight radius curves. And some terminus station approaches can be slow. Upminster for example - has 10mph and 15mph approach speeds.

 

[Nym]

I think the slowest would be 3 mph on and off the traverser and the outside pit at Acton Works, but I’m not sure if that’s signed or not.

I think it’s only the Bombardier engineers that designed it that will know the true top speed of the S Stock.

But for context, the 1972TS is “rated” for 45, but has been significantly faster before on test runs.

 

[The0]

They should have a really fast test track were they go all out with train on test to find the top speed

 

[trebor79]

Is it just me or is the Piccadilly line much slower in the central London tunnels that it used to be. Feels like a real trundle these days whereas in the past it was very similar to the other lines.

 

[Dstock7080]

Upminster for example - has 10mph and 15mph approach speeds.

Upminster pfm.3 is 7mph; pfm.4 11mph, pfm.5 14mph

They should have a really fast test track were they go all out with train on test to find the top speed

They did substantial testing at Derby and Old Dalby before delivery to London

 

[The0]

I have seen videos of s stock test runs but they didn't seem to go more than 45mph from what I could see (although it was quite hard to tell so I could be incorrect)

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

A few weeks ago I want on a district line between Elm park and Dagenham East and the train (wich was on cbtc) cut out at 45mph even though its the longest distance on the district line (1.4miles) and the district line reaches roughly 60mph between upney and becontree (a distance of 1.1miles) dose anyone know why the trains are going slower on a longer stretch of track when both are completely straight.

 

[DelW]

They should have a really fast test track were they go all out with train on test to find the top speed

To do that, the mythical "they" would have to spend a lot of money for no practical benefit whatsoever.

Siemens have added a stretch of 4-rail electrification to their test track in Germany, which might have a higher permitted speed than those mentioned above.

 

[hexagon789]

Didn't a set of A stock touch 74mph 'unofficially' on one of the (then) 70 sections on the Met during its farewell trip?

Any advance on 74mph for LU stock...?

 

[The0]

Didn't a set of A stock touch 74mph 'unofficially' on one of the (then) 70 sections on the Met during its farewell trip?

Any advance on 74mph for LU stock...?

You get loads of the story's of a stocks reaching 70mph but I have no idea if they are true

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

Wiki has it down at 70mph (though it's not always reliable)

 

[hexagon789]

You get loads of the story's of a stocks reaching 70mph but I have no idea if they are true

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

Wiki has it down at 70mph (though it's not always reliable)

The A stock was built and authorised for 70 when new. That was also the line limit on the Met fast lines.

In around 2000, the maximum speed of the A stock was restricted (by notice, nothing was done mechanically) to 50mph.

For the farewell tour, I understand that 70mph running was sanctioned but that a number of recorders on board clocked a maximum of 74.

 

[Dstock7080]

The Metropolitan was signed for 70mph running and A Stock regularly achieved that, certainly heading southbound from Chalfont to Moor Park, (I was on the Line 1985-1987)

 

[The0]

The A stock was built and authorised for 70 when new. That was also the line limit on the Met fast lines.

In around 2000, the maximum speed of the A stock was restricted (by notice, nothing was done mechanically) to 50mph.

For the farewell tour, I understand that 70mph running was sanctioned but that a number of recorders on board clocked a maximum of 74.

Dose anyone know why the line speed was decrease I bet the s stock could do 70 if not 75mph

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

They can reach 60 at ease

 

[bramling]

Didn't a set of A stock touch 74mph 'unofficially' on one of the (then) 70 sections on the Met during its farewell trip?

Any advance on 74mph for LU stock...?

There are numerous tales from very old-hand drivers of A stock going *well* above 70 mph in times past, especially when running non-stop down from Amersham.

As regards the farewell tour, from what I gather there was some hot water regarding the speed the train got up to. It certainly reached the 70s, and as a result of the various GPS screenshots floating around the internet eyebrows were raised in certain places which then resulted in the aforementioned hot water.

As an aside, I can just about remember travelling on A stock in the 90s when they routinely exceeded 50 mph and it was certainly quite hair-raising. As for that matter was the Central Line in the early 2000s when 100kph running was allowed with the 92 stock and at the time there were still sections of bullhead rail on the open sections on which the 100kph was achieved. Northolt to South Ruislip really was quite something, probably more spectacular than the Met due to Tube stock being lower down, but it didn’t last as the track was replaced, also at around the same time the speed dropped to 85kph following the Chancery Lane derailment and has been the case ever since.

Nowadays Kennington to Waterloo northbound offers a decent run on rough track albeit at 50 mph. Highgate to Archway southbound isn’t bad either though from memory tops at 47 mph.

 

[pdeaves]

Also what's the slowest speed on the tube and were is it?

0mph; stations and sidings...

 

[12LDA28C]

With limiters off can an s stock reach over 60mph or can it's motors actually not go over 60

== Doublepost prevention - post automatically merged: 25 Jul 2023 ==

Also what's the slowest speed on the tube and were is it?

The tripcock system on the LU only allows for a maximum speed of 60mph anyway so the question is moot.

 

[Dstock7080]

The tripcock system on the LU only allows for a maximum speed of 60mph anyway so the question is moot.

Much of the sub-surface Lines now operate CBTC without tripcocks and has been mentioned did operate to 70mph with them.

 

[12LDA28C]

Much of the sub-surface Lines now operate CBTC without tripcocks and has been mentioned did operate to 70mph with them.

Indeed but that was many years ago and would not be permitted these days. The tripcock only claims to stop a train within the overlap after a SPaD at speeds up to 60mph.

 

[Mikey C]

The A stock was built and authorised for 70 when new. That was also the line limit on the Met fast lines.

In around 2000, the maximum speed of the A stock was restricted (by notice, nothing was done mechanically) to 50mph.

For the farewell tour, I understand that 70mph running was sanctioned but that a number of recorders on board clocked a maximum of 74.

70mph on most mainline stock feels slow and steady, whereas 70mph on the A stock was an exciting ride! Very bouncy I recall

 

[The0]

This is a bit off topic but why is the tube always such a bouncy ride even at slow speeds is it just a matter of track quality

 

[Railperf]

Much of the sub-surface Lines now operate CBTC without tripcocks and has been mentioned did operate to 70mph with them.

There were claims that well over 70mph was achieved with A stock back in the day- mainly ECS non stop runs downhill from Amersham to Rickmansworth but at those speeds the back EMF from the DC motors was effectively equal to the traction current creating an almost natural speed limiter.

 

[Snow1964]

This is a bit off topic but why is the tube always such a bouncy ride even at slow speeds is it just a matter of track quality

Partly track quality, but mainly due to lack of space restricting the size of shock absorbers, coupled to relatively short wheelbase bogies. Also a crush loaded tube car is something like 3 times weight of empty one, so the stiffness of springing is rather a compromise.

 

[The0]

Partly track quality, but mainly due to lack of space restricting the size of shock absorbers, coupled to relatively short wheelbase bogies. Also a crush loaded tube car is something like 3 times weight of empty one, so the stiffness of springing is rather a compromise.

I sware met line trains have better track quality

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

They just aren't as bouncy (this is past finchley Rd)

 

[Railperf]

Partly track quality, but mainly due to lack of space restricting the size of shock absorbers, coupled to relatively short wheelbase bogies. Also a crush loaded tube car is something like 3 times weight of empty one, so the stiffness of springing is rather a compromise.

That would also explain why tube train maximum speeds are not much more than 60mph. A combination of poor quality track and inadequate suspension system for higher speeds.

 

[Dstock7080]

There were claims that well over 70mph was achieved with A stock back in the day- mainly ECS non stop runs downhill from Amersham to Rickmansworth but at those speeds the back EMF from the DC motors was effectively equal to the traction current creating an almost natural speed limiter.

A Stock speedos were marked up to 70, two further unnumbered marks were evenly spaced after 70 and I have seen the first mark reached.

 

[The0]

They should really just upgrade the track I can think of quite a few areas where the tube could do more than 60

 

[gswindale]

They should really just upgrade the track I can think of quite a few areas where the tube could do more than 60

What would be the benefit - it would take slightly longer to then reach "top speed" and you'd have to brake earlier. You would, I would think, at best save a few seconds on the overall journey time.

 

[The0]

What would be the benefit - it would take slightly longer to then reach "top speed" and you'd have to brake earlier. You would, I would think, at best save a few seconds on the overall journey time.

Maybe on bits like fast met line tho still fair point

 

[12LDA28C]

That would also explain why tube train maximum speeds are not much more than 60mph. A combination of poor quality track and inadequate suspension system for higher speeds.

And the tripcock system where that is in use as already mentioned.

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

They should really just upgrade the track I can think of quite a few areas where the tube could do more than 60

Not in tripcock-fitted areas they couldn't.

== Doublepost prevention - post automatically merged: 26 Jul 2023 ==

Maybe on bits like fast met line tho still fair point

No.