The APT project and what may have been

[43074]

One way to look at APT's funding was as APT vs ECML wiring, the NSE upgrade, Sprinterisation... You could argue that those were equally valid uses of the funding...

Even better if there were APTs on the East Coast Main Line - then we could have had (and still would have had) a world leading railway, running at 155mph. The ECML benefitted from all of the above - NSE modernisation in the form of 365s, electrification and sprinterisation of umpteen different services based around the ECML. The WCML on the other hand...

Another BR casulty were the IC250 trains, designed for the WCML after APT failed - it could also have got the ECML up to 160mph over a period of upgrades - IC director John Prideaux was speaking of replacing IC225s with IC250s by 1997 (he said this in 1991); the displaced 225s would have gone to the MML electrification. Yet another 'what might have been' of BRs InterCity sector.

 

[Wyvern]

Even better if there were APTs on the East Coast Main Line - then we could have had (and still would have had) a world leading railway, running at 155mph. The ECML benefitted from all of the above - NSE modernisation in the form of 365s, electrification and sprinterisation of umpteen different services based around the ECML. The WCML on the other hand...

Another BR casulty were the IC250 trains, designed for the WCML after APT failed - it could also have got the ECML up to 160mph over a period of upgrades - IC director John Prideaux was speaking of replacing IC225s with IC250s by 1997 (he said this in 1991); the displaced 225s would have gone to the MML electrification. Yet another 'what might have been' of BRs InterCity sector.

All of this was and is negated by the limitations on conventional signalling.

The problem isnt going faster. It's stopping.

 

[43074]

Stopping wasn't a problem for APT - It had sophisticated hydro-kinetic brakes (which used small water turbines to slow the wheels), which meant it could stop within existing signal stopping distances (APT-E did 154mph on the Great Western, and APT-P did 162.7 down Beattock bank). The problem with the hydro-kinetic brakes though was that they froze at sub zero temperatures - no fluid, no brakes.

 

[Eagle]

The problem with the hydro-kinetic brakes though was that they froze at sub zero temperatures - no fluid, no brakes.

To which the solution, surely, is to use a liquid with a much lower freezing point? (And similar viscosity and density and all that.)

 

[Kali]

Do you know where I can find information about APT-C? I've done a quick Google search and can't find anything. What with ERTMS being installed across the UK eventually, and TASS currently being used on the WCML (and APT being used on the GWML), I am interested to see how they compare.

Yeah, I always get that the wrong way round: it was C-APT, you can find a little info here along with more general info about the class. It's basically EPS displayed in the cab.

The tilt system worked by calculating cant deficiency continuously, some of the surviving docs have a lot of detail about it - I can't help thinking most of the problems were just down to it being a prototype ( other than the powercars, which is just down to it being a stupid thing to do ). The pendolino tilt system is actually older, I think - at least originated earlier anyway.

 

[LE Greys]

All of this was and is negated by the limitations on conventional signalling.

The problem isnt going faster. It's stopping.

Which was presumably why BR had trials for flashing green signals and ATP in various areas, noteably Stoke Bank and the GWML.

 

[Wyvern]

A couple of quick notes.

THe IC225s can go faster than 125mph but dont because of signalling limitations.

My understanding is that it was the conventional brakes that froze

HOwever it is true that braking distances could not be guaranteed under adverse rail conditions.

THere were tilting trains prior to APT. but they were passive pendular tilt. It was BR that went to town on active tilt.

 

[ryan125hst]

Yeah, I always get that the wrong way round: it was C-APT, you can find a little info here along with more general info about the class. It's basically EPS displayed in the cab.

The tilt system worked by calculating cant deficiency continuously, some of the surviving docs have a lot of detail about it - I can't help thinking most of the problems were just down to it being a prototype ( other than the powercars, which is just down to it being a stupid thing to do ). The pendolino tilt system is actually older, I think - at least originated earlier anyway.

Thank You
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Even better if there were APTs on the East Coast Main Line - then we could have had (and still would have had) a world leading railway, running at 155mph. The ECML benefitted from all of the above - NSE modernisation in the form of 365s, electrification and sprinterisation of umpteen different services based around the ECML. The WCML on the other hand...

Another BR casulty were the IC250 trains, designed for the WCML after APT failed - it could also have got the ECML up to 160mph over a period of upgrades - IC director John Prideaux was speaking of replacing IC225s with IC250s by 1997 (he said this in 1991); the displaced 225s would have gone to the MML electrification. Yet another 'what might have been' of BRs InterCity sector.

Just think how good our railway network would be if the APT's went into service, and then replaced by IC250's in the mid to late 90's. The APT's could have been used on other lines or maybe even sold abroad, leaving the 225's to go to the MML. Alternatively, the APT's could have been used on the MML and the 225's could have been used on the Anglian line (what's it official name? I can't remember! ). If the HST's remained in service after all of that as they are now, we would have a world leading rail network for sure.

It's a shame that the APT and the IC250, two trains that were to be revolutionary, were cancelled. There wasn't even a prototype of the IC250 was there? Am I correct in saying they only got as far as a mock up?

 

[ainsworth74]

Just think how good our railway network would be if the APT's went into service, and then replaced by IC250's in the mid to late 90's.

If APT-S (in whatever form) had gone ahead we wouldn't have seen IC250s. APT-S wouldn't be entering squadron service until at best the late 80s and more likely the early 90s. Why on earth would you then go and design yet another train to enter service a few years later?

we would have a world leading rail network for sure

We might not be world leaders but we do have, in my opinion, a world class network.

 

[LE Greys]

If APT-S (in whatever form) had gone ahead we wouldn't have seen IC250s. APT-S wouldn't be entering squadron service until at best the late 80s and more likely the early 90s. Why on earth would you then go and design yet another train to enter service a few years later?

That's quite likely. Probably, they would have been working on APT's successor (perhaps a tilting version of Eurostar) sometime around then, with planned entry into service around 2000. BREL would have had other fish to fry, with some version of the Networker Project, various Sprinter descendants and some form of new freight loco, perhaps a Class 38 or an electric Class 88, in the pipeline before this new replacement.

If it did happen, it would probably be called APT-2, perhaps changing to IEP later on. The exact order that things happen in depends on whether privatisation happens and how much Eurostar technology transfers over.

 

[RobShipway]

What routes out of Waterloo would the HST's have done, if there had been a APT-D as surely there is too many HST's for the Waterloo - Exeter route?

 

[sprinterguy]

Even better if there were APTs on the East Coast Main Line - then we could have had (and still would have had) a world leading railway, running at 155mph.

The 155mph requirement of the APT was dropped from the production proposals quite early on, certainly by 1981. The maximum speed of the production APT trains would have mirrored that of the IC225s: 125mph to begin with, with the possibility of an increase to 140mph dependent on the installation of suitable signalling at a later date.
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Concorde does predate APT by a long way (being a 1960s project).

APT was a 1960s project. It formerly commenced in November 1968. It just took a long time to get off the ground and the form of the electric APT trains was not finalised until 1973.
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I have also heard references to APT-D, so I suspect that the GWML would have been given the tilting treatment as well. A BR 'Voyager'?

I do not believe that British Rail ever had intentions of producing a diesel APT. Two types of APT were initially proposed, electric and gas turbine as it was felt that diesel power was not viable, as above 125mph the ratio between power and mass becomes very poor. The first application of the APT was expected to be on the Newcastle to Bristol Crosscountry route utilising gas turbine trainsets , but the 1973 fuel crisis and a sharp rise in the cost of oil put paid to Leyland's development of gas turbine engines. Plus by 1973 the HST project was in full swing, so there was no need for a self-powered version of the APT as the HSTs would cover the non-electrified routes and attention was focused on developing an electric APT coupled with a rolling programme of electrification that would see the HSTs cascaded to secondary routes as the main lines were electrified and APTs introduced.

"APT-D" was the designation given to the one APT-P trainset that was used for trials and test running post 1984 in order to develop the Intercity 225 trains. Testing the Brecknell Willis high speed pantograph and the like. The "D" stood for Development.
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What routes out of Waterloo would the HST's have done, if there had been a APT-D as surely there is too many HST's for the Waterloo - Exeter route?

There's nothing to say that the Waterloo to Exeter route would have to take on all ninety five HST trainsets. HSTs were also expected to be cascaded onto routes such as Edinburgh to Glasgow (Which actually ended up with class 47s and push-pull mark 3 sets instead) and Transpennine North, and there would still be a requirement for HSTs on routes such as London to Aberdeen and Inverness in just the same way as there has been ever since the ECML was electrified.
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That's quite likely. Probably, they would have been working on APT's successor (perhaps a tilting version of Eurostar) sometime around then, with planned entry into service around 2000.

That is assuming that the APT had gone into squadron service at the earliest proposed date (Which I think was 1976). If BR had persevered with the APT project beyond the development period that actually transpired, then we wouldn't have seen production APTs until a similar date to when the IC225s were introduced, so there is no way that the APTs would have been due for withdrawal in 2000. More like 2020 at the earliest.
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If anybody is interested, here is the last discussion that we had on exactly this subject:
http://www.railforums.co.uk/showthread.php?t=72074&highlight=APT+development

 

[LE Greys]

I do not believe that British Rail ever had intentions of producing a diesel APT. Two types of APT were initially proposed, electric and gas turbine as it was felt that diesel power was not viable, as above 125mph the ratio between power and mass becomes very poor. The first application of the APT was expected to be on the Newcastle to Bristol Crosscountry route utilising gas turbine trainsets , but the 1973 fuel crisis and a sharp rise in the cost of oil put paid to Leyland's development of gas turbine engines. Plus by 1973 the HST project was in full swing, so there was no need for a self-powered version of the APT as the HSTs would cover the non-electrified routes and attention was focused on developing an electric APT coupled with a rolling programme of electrification that would see the HSTs cascaded to secondary routes as the main lines were electrified and APTs introduced.

"APT-D" was the designation given to the one APT-P trainset that was used for trials and test running post 1984 in order to develop the Intercity 225 trains. Testing the Brecknell Willis high speed pantograph and the like. The "D" stood for Development.

Curious. I can't remember where the idea came from unless someone was engaging in a bit of 'futurology' about the HST's successor.

There's nothing to say that the Waterloo to Exeter route would have to take on all ninety five HST trainsets. HSTs were also expected to be cascaded onto routes such as Edinburgh to Glasgow (Which actually ended up with class 47s and push-pull mark 3 sets instead) and Transpennine North, and there would still be a requirement for HSTs on routes such as London to Aberdeen and Inverness in just the same way as there has been ever since the ECML was electrified.

And London-Norwich. This was before electrification began to go northwards. The MML and inter-regional (which later became XC) would retain HSTs for the forseeable future. Full details can be found in Peter Semmens' Speed on the East Coast Main Line. I'm not sure what would happen to the Aberdeen and Inverness routes, but APTs being dragged by 47s would be another option, although it's likely that internal Scottish routes would see 2+7 (or 1+4) HSTs.

That is assuming that the APT had gone into squadron service at the earliest proposed date (Which I think was 1976). If BR had persevered with the APT project beyond the development period that actually transpired, then we wouldn't have seen production APTs until a similar date to when the IC225s were introduced, so there is no way that the APTs would have been due for withdrawal in 2000. More like 2020 at the earliest.

I was more thinking 'cascade' than 'retirement'. I'd suspect that the MML and GEML would receive wires around 2000, inheriting former WCML or ECML stock, depending on what was replaced first. 2020 sounds likely for a final withdrawl.

 

[Kali]

HSTs aren't really suitable for Waterloo-Exeter anyway, not without some regearing at least; they have terrible tractive effort, hence the rather slow acceleration.

I do wonder if the whole APT project was barking up the wrong tree slightly - I realise that a new train which uses existing infrastructure ( although it wasn't - it was relying on all the existing routes being electrified ) was pretty much all we could afford, but in the end we're looking at building new infrastructure anyway. I wonder if they could have sold putting high-speed rail routes down the centre of the motorway network if someone had thought of it.

 

[ryan125hst]

If APT-S (in whatever form) had gone ahead we wouldn't have seen IC250s. APT-S wouldn't be entering squadron service until at best the late 80s and more likely the early 90s. Why on earth would you then go and design yet another train to enter service a few years later?



We might not be world leaders but we do have, in my opinion, a world class network.

That's a good point-I think i'm a bit out on the dates! I was thinking more early 80's, so they would have been around 20 years old at the time of the IC250's. As you say though, the IC250's (and maybe even the 225's) would never have been invented if the APT was successful. It was all before my time though, so I do have an excuse

 

[ainsworth74]

As you say though, the IC250's (and maybe even the 225's) would never have been invented if the APT was successful.

I think we can be certain that 225s would never have existed as in the real world time line they were built at about the same time APTs would have been built in our 'what if' timeline. Just for clarity APT-E was in service from 1972 - 1976 and APT-P from 1980 to 1986. It is therefore safe to assume that APT-S would have been delivered from the late eighties onwards which is exactly the same time as the 225s were delivered.

If APT had been procured then IC225 and IC250 would not have even been thought about as APT-S would have become the standard long distance train that BR used on electrified routes.

 

[RobShipway]

I wonder if APT had been successful, if you would have had a DEMU version of it, that would be able to have a pantograph for electrified lines, but run on diesel power for none electrified lines?

 

[IanBanks-Jones]

It is doubtful. Dragging a dead power car around in whatever mode ruins the cost effectiveness (and acceleration) of a unit. That's why a feasable dual mode MU has never been built.

But if we're hypothesising, I'm sure the RTC would've cracked the engine weights by now...

 

[sprinterguy]

I wonder if APT had been successful, if you would have had a DEMU version of it, that would be able to have a pantograph for electrified lines, but run on diesel power for none electrified lines?

As far as I know diesel power was never considered for the APT project. And in a hypothetical scenario, when the next generation of electric Intercity trains following APT would be required, I doubt that an "APT2" would be developed any more than the HST design is being perpetuated by the design of it's successor, the IEP (I.e. not at all).

 

[Eagle]

I wonder if APT had been successful, if you would have had a DEMU version of it, that would be able to have a pantograph for electrified lines, but run on diesel power for none electrified lines?

That would be an EDMU (or bimodal MU). A DEMU, for example a Voyager, doesn't take electric power.

 

[transmanche]

That's why a feasable dual mode MU has never been built.

*cough* AGC *cough*

 

[IanBanks-Jones]

Point taken. My knowlege of continental railways stops with the TGV. The power and acceleration aren't at APT levels though, are they?

 

[Moog_1984]

To which the solution, surely, is to use a liquid with a much lower freezing point? (And similar viscosity and density and all that.)

They did, you can see the ethylene glycol mentioned on various cut away diagrams of the APT. It was a very cold winter when the launch took place so they probably did not have enough antifreeze. Water alone has a lot of issues so a production APT would have probably had synthetic hyrdaulic fluid developed for the job.

Do Mrk Ivs have hydro-kinetic braking BTW?

Which was presumably why BR had trials for flashing green signals and ATP in various areas, noteably Stoke Bank and the GWML.

Yeah that is the reason to show that the next section is also green apparently.

The design breif was actually 170mph orginally and the train ran regularly at 150mph on many sections north of Crewe. I dont read anywhere that 155mph peak or sustained speeds where track and signalling allowed for it was ever dropped during this project.

I really don't see the APT - P (prototype ) as being a failure by any means- political failure or meddling yes, PR disaster yes. 787 flight anyone?

The problems with the kinetic brakes and the final friction brake system were fixed, the pantograph was replaced by a compeletly safe one and the tilting mechanisms were brought to a level of reliability acceptable for them being prototypes. The tilting system was still prototype and the passenger nausea issue was known about and addressed with subsequent designs around Europe.

Even a compromise to sustained 125mph running and fewer stops in the mid eighties would have been a major improvement on the WCML timings, and there-in lay the political issue: the recently privatised British Airways had the Glasgow-Heathrow route as a major cash cow and feeder to international flights. Also there were few tory seats in the NW and west of scotland. A sub 4 hour journey time city-centre to centre would have threatened the actual flight plus airport - city centre time

At the time I was very surprised we got wires on the ECML and Ayr route, but then again there were plenty Tory seats on the ECML in north yorkshire, durham and so on, and Ayr was held by the tories.

There are several legacies of the APT : of course the 225s which I had at 140mph once, quite impressive, and of course there was paving the way for Platiclinos and Vomitager DEMUs.

The final one is that tilting and going faster than 140mph are "two quantum leaps" as quoted from the documentary on the IC225s . In other words, if you want to go fast, then do what the french did and build HS2.

 

[gimmea50anyday]

MkIV use conventional disc brakes. Each trailer axle has 3 brake discs attached to them, plus the loco if you look at the bogies you will see a disc brake for the loco behind and directly attached to the motor drive shaft

 

[LE Greys]

They did, you can see the ethylene glycol mentioned on various cut away diagrams of the APT. It was a very cold winter when the launch took place so they probably did not have enough antifreeze. Water alone has a lot of issues so a production APT would have probably had synthetic hyrdaulic fluid developed for the job.

Do Mrk Ivs have hydro-kinetic braking BTW?

Just plain old disc brakes, IIRC. That's one reason they've always been restricted to 125 on existing signalling.

Yeah that is the reason to show that the next section is also green apparently.

The design breif was actually 170mph orginally and the train ran regularly at 150mph on many sections north of Crewe. I dont read anywhere that 155mph peak or sustained speeds where track and signalling allowed for it was ever dropped during this project.

I really don't see the APT - P (prototype ) as being a failure by any means- political failure or meddling yes, PR disaster yes. 787 flight anyone?

The problems with the kinetic brakes and the final friction brake system were fixed, the pantograph was replaced by a compeletly safe one and the tilting mechanisms were brought to a level of reliability acceptable for them being prototypes. The tilting system was still prototype and the passenger nausea issue was known about and addressed with subsequent designs around Europe.

Even a compromise to sustained 125mph running and fewer stops in the mid eighties would have been a major improvement on the WCML timings, and there-in lay the political issue: the recently privatised British Airways had the Glasgow-Heathrow route as a major cash cow and feeder to international flights. Also there were few tory seats in the NW and west of scotland. A sub 4 hour journey time city-centre to centre would have threatened the actual flight plus airport - city centre time

At the time I was very surprised we got wires on the ECML and Ayr route, but then again there were plenty Tory seats on the ECML in north yorkshire, durham and so on, and Ayr was held by the tories.

There are several legacies of the APT : of course the 225s which I had at 140mph once, quite impressive, and of course there was paving the way for Platiclinos and Vomitager DEMUs.

The final one is that tilting and going faster than 140mph are "two quantum leaps" as quoted from the documentary on the IC225s . In other words, if you want to go fast, then do what the french did and build HS2.

From what I remember, they planned a timetable around 125 running, but with 'authorised overspeed' up to 150, but still including a 4-hour Royal Scot service. Most of the press runs tried to stick to this, including the 4 hr 2 minute run I had the privilage of breaking, but in general they had to authorise the overspeed for various reasons. Most of this comes from various recollections of books by Peter Semmens, who was on-board most of the test runs.

 

[Manchester77]

Would the controlled over speeds been controlled using CAPT?

 

[cjmillsnun]

Stopping wasn't a problem for APT - It had sophisticated hydro-kinetic brakes (which used small water turbines to slow the wheels), which meant it could stop within existing signal stopping distances (APT-E did 154mph on the Great Western, and APT-P did 162.7 down Beattock bank). The problem with the hydro-kinetic brakes though was that they froze at sub zero temperatures - no fluid, no brakes.

That wasn't the problem with the APT brakes. The HK system used a glycol (antifreeze) mixture. The problem was the moisture in the air system of the tread brakes freezing.