APT vs Pendolino Tilt Mechanisms / Sickness

[mallard]

I traveled from Euston to Preston on the APT on 24th August 1984, along with my two sons. None of us felt sick at all, nor did anybody else in the coach we were in.

Of course, adjustments and modifications were made to the tilt system by that point and when it was operating in public service it ran at a lower speed; "officially" limited to 125mph (it ran at up to 140mph in the 1981 press runs), but frequently slower than that due to following the 100/110mph WCML regulars.

 

[dgl]

The original Pendolino, and the tilting Talgos and I think the LRC in Canada also, used a passive tilt system. Basically the train is suspended from a pivot high up and swings outwards like a pendulum in response to the centrifugal forces. This has the obvious disadvantage that the pivot and its supports intrude into what would otherwise be passenger service. The lower parts of the train swinging outward probably mean it would have to be even narrower in this area to clear British platforms (and hence have a big gap when stopped at those platforms). The move outward of the centre of gravity also increases the risk of overturning on curves, but this may be insignificant relative to other factors that limit curving speed.

The APT and the current Pendolino use an active tilt system where the body is actually rotated around an axis which roughly coincides with the centre of gravity, which therefore does not move much. This can apply tilt more accurately and quickly than a passive system and the body narrowing higher up is less of a constraint on the interior or the stepping distances.

Looking at the FIAT Ferrovia wikipedia article it would seem to be that they were active systems rather than the passive systems inverted/used b other companies such as Talgo.

 

[Rail Blues]

I get motion sickness on tilting trains as they hit the Scottish Southern uplands without fail - booze or no booze. I think it is the number of s curves and switchbacks that does it. I live in Edinburgh so I can always tell I'm nearly home as I start feeling the need to upchuck.

 

[daikilo]

I have always thought that the problem with the APT was it was too big a step for BR. They did a very good job to get where they did, but they still weren't at the end of the story and didn't have a certain path to get there.

The HST proved what BR were comfortable with, and a push-pull electric version could have worked (the two power cars in the centre of the APT were almost solely to avoid more than one pantograph, and look how the Pendo has solved the problem, or the TGV). If only they could have teamed up aith say GEC-Alsthom.

 

[whhistle]

My old dear who is now in her early 70s hates the pendolinos - she is always complaining of motion sickness when travelling on them

You also have the fact she knows she's tilting.
Take that out and I bet some of the symptoms will disappear.


It's a shame I never travelled onthe APT.
Would love to see what it was really like!

Didn't British rail sell their research and patents to fiat? So the pendilino is essentially an improvement of the ATP

People say this but I have yet to see any documentation to confirm.

 

[cambsy]

I wish I could have travelled on the APT, did try go on one in the 80’s but ended up on an 87 and mk2 set, I have done many hundred of hours on the Pendolino’s, quite often London-Glasgow and straight back, watched films, slept etc, not a problem at all, in fact I enjoy a good tilting blast, one does feel the tilting a little bit, which helps, The Pendolino can tilt more due to body side curving in more, so fit in loading gauge when tilting at 8-9 degrees, this why its more cramped inside than the Super Voyager, there are different speed limits around certain curves for Pendolino and Super Voyager, the Super voyager has the lower speed on these curves, so a Pendolino will give a faster run than a Super voyager, only time ever felt travel sick was on Condor Ferries Hydrofoil in choppy seas, the motion was appalling and nearly felt sick until went outside and could see the horizon more.

 

[GrimShady]

The HST proved what BR were comfortable with, and a push-pull electric version could have worked (the two power cars in the centre of the APT were almost solely to avoid more than one pantograph, and look how the Pendo has solved the problem, or the TGV). If only they could have teamed up aith say GEC-Alsthom.

BR had planned an electric HST but canceled the order.

They were concerned about oscillations in the contact wire from two pantographs at 140 mph, also running a high voltage cable along the train was considered, there was a safety concern here.

Have a look at APT-S, they had solved the problems. IC225 is what APT became minus the tilt system which was supposed to be fitted at a later stage if the MK4 order went head for WCML

 

[ericlesley]

"Fiat acquired patents for the tilting technology used in the UK’s Advanced Passenger Train (APT) project in 1982. APT was an unsuccessful experimental project developed by British Rail.

Fiat made several improvements over the original technology and introduced an advanced first generation-ETR 450 on the Rome-Milan route. It was the first Pendolino to enter regular service."

https://www.railway-technology.com/projects/pendolino-train/

 

[The_Engineer]

IC225 is what APT became minus the tilt system which was supposed to be fitted at a later stage if the MK4 order went head for WCML

Having worked on the design of Mk.IV vehicles I can assure you they owe nothing to APT vehicle design, structurally or functionally. It was a clean sheet design by Metro-Cammell to a new BR specification. Likewise the Class 91 locomotive from GEC Traction. Yes, body profile and space was allowed for tilt equipment to be integrated into the design later but that's all.

 

[GrimShady]

Having worked on the design of Mk.IV vehicles I can assure you they owe nothing to APT vehicle design, structurally or functionally. It was a clean sheet design by Metro-Cammell to a new BR specification. Likewise the Class 91 locomotive from GEC Traction. Yes, body profile and space was allowed for tilt equipment to be integrated into the design later but that's all.

I'm aware it was a clean sheet, my intent was that IC225 was the next design featuring many of the lessons from APT and also the same formation as the proposed APT Squadron fleet. As far as I'm aware Class 91 was heavily based on the APT power car minus tilt and having the traction motors slung underneath the body instead of inside.

Additionaly one short APT-D set was used in the development of Mk4 which I assume you'll know about.

As far as i'm aware IC225 started life as part of the APT project however another brand was selected in order to distance the project from APT-P.

 

[daikilo]

I'm aware it was a clean sheet, my intent was that IC225 was the next design featuring many of the lessons from APT and also the same formation as the proposed APT Squadron fleet. As far as I'm aware Class 91 was heavily based on the APT power car minus tilt and having the traction motors slung underneath the body instead of inside.

Additionaly one short APT-D set was used in the development of Mk4 which I assume you'll know about.

As far as imI aware IC225 started life as part of the APT project however another brand was selected in order to distabce the project from APT-P.

Never heard of an APT-D.

Equally, never heard of any link between cl91+Mk4 and APT, rightly or not.

Once HST service was fully introduced on EC, I would imagine local 140mph was a challenge. I even think IC225 was a gimmick to justify OHLE, and it has failed

 

[GrimShady]

Never heard of an APT-D.

Equally, never heard of any link between cl91+Mk4 and APT, rightly or not.

Once HST service was fully introduced on EC, I would imagine local 140mph was a challenge. I even think IC225 was a gimmick to justify OHLE, and it has failed

There are pictures of APT-D out there.

140mph was possible but required a change to signaling, it was trailed on the ECML using a flashing green indicating the next signal was solid green, again sadly this never went anywhere.

The original plan for ECML was Class 89 and MK3 however it was felt that this didn't offer much over what IC125 was already doing hence the development of APT-U or IC225 as it became.

In what way has IC225 failed?

 

[61653 HTAFC]

It doesn't do 225km/h for one thing!

 

[The_Engineer]

It doesn't do 225km/h for one thing!

It was designed to work up to 225 km/hr (140 mph) and only track prevents it from doing so. I can confirm from first hand experience it goes very well up to 162.4 mph (260 km/hr)...…

 

[61653 HTAFC]

It was designed to work up to 225 km/hr (140 mph) and only track prevents it from doing so. I can confirm from first hand experience it goes very well up to 162.4 mph (260 km/hr)...…

OK, they don't do 225 in service then!

Agree it isn't the fault of the trains!

 

[GrimShady]

It was designed to work up to 225 km/hr (140 mph) and only track prevents it from doing so. I can confirm from first hand experience it goes very well up to 162.4 mph (260 km/hr)...…

That must have been some experience!

 

[GrimShady]

Here's a proposed drawing of an APT-S power car.

 

[cjmillsnun]

I also recall that APT has what is called reactive tilt, so on entering a curve there's a lag before tilt kicks in and corrects the forces. Tilt on the WCML is achieved by the train detecting balises just before the curve which, with a speed calculation, allows tilt to come in right at the start of the curve. In other word the trains "anticipates" the curve. It was thought this made a big difference in the prevention of nausea.

It was a reactive tilt, however it used the car in front for the detection, so that the lag was effectively cancelled out, meaning that the front car was the only one that had a delayed reaction.

 

[cjmillsnun]

I have always thought that the problem with the APT was it was too big a step for BR. They did a very good job to get where they did, but they still weren't at the end of the story and didn't have a certain path to get there.

The HST proved what BR were comfortable with, and a push-pull electric version could have worked (the two power cars in the centre of the APT were almost solely to avoid more than one pantograph, and look how the Pendo has solved the problem, or the TGV). If only they could have teamed up aith say GEC-Alsthom.

At the time a 25kV bus running the length of the train was not allowed on British trains. Thankfully the experience with TGV allowed minds to be changed over this.

 

[Bromley boy]

The APT is one of the big what if's - I also wonder if the problems with the ride were as bad as were suggested ( the problems with the project seem clear!)

I saw a documentary about it a few years back which suggested the “ride issue” was mostly down to the press pack for the inaugural southbound run having stinking hangovers, having been wined and dined in Glasgow the night before...

 

[USRailFan]

Here's a proposed drawing of an APT-S power car.

"Squadron"? Was really BR terminology that militarised, or was it just a common expression even outside the military?

 

[ac6000cw]

'Squadron' was a term that BR used at the time e.g. 'in squadron service' when a new fleet of trains was fully introduced. Maybe it was favourite term of someone in BR's PR office at the time?

I suspect it was trying to borrow a bit of allure from the aeronautical world, rather than use the term 'fleet' (borrowed from the nautical world).

 

[swaldman]

The Voyagers tilt even less than the Pendolinos (6° vs 8°), although I wonder if there is also anything to do with other factors like the larger windows?

I thought the Voyagers (as opposed to Super Voyagers) didn't tilt at all? Or am I wrong?

I've never had a problem on Pendalinos or Super Voyagers, but I do feel a little travel sick on Shinkansen N700 series trains. I'm guessing that perhaps their tilt, while I think mild in angle, is closer to the APT's problem of full compensation (it wouldn't take much, given that they already have banked high speed track)

 

[ac6000cw]

It was designed to work up to 225 km/hr (140 mph) and only track prevents it from doing so. I can confirm from first hand experience it goes very well up to 162.4 mph (260 km/hr)...…

My memory from the time was that BR InterCity eventually decided that the economics of 140 mph operation didn't stack up - increased maintenance costs of track and rolling stock, increased energy costs and reduced line capacity. Also possibly having to install some form of cab signalling or at least proper automatic train stops (e.g. the equivalent of TPWS) before the Railway Inspectorate might allow day-to-day 140 mph operation (the flashing greens north of Peterborough were intended just for testing purposes I think).

 

[Intercity Exec]

I thought the Voyagers (as opposed to Super Voyagers) didn't tilt at all? Or am I wrong?

I've never had a problem on Pendalinos or Super Voyagers, but I do feel a little travel sick on Shinkansen N700 series trains. I'm guessing that perhaps their tilt, while I think mild in angle, is closer to the APT's problem of full compensation (it wouldn't take much, given that they already have banked high speed track)

You are right about the Voyagers not having tilt mechanisms, only Super Voyagers have the TASS system fitted. CrossCountry locked out the tilt system on their Super Voyagers early on in the franchise to boost unit reliability as it was said to be a fairly regular cause of failure. I had heard that some equipment was also removed but I do not know if this is true, if it is then it wouldn't be hard to reattach it and probably required on return to the ROSCO.

The Nozomi N700 Shinkansen only tilt 1 degree to provide an assistance to increase comfort round corners and should therefore not fully compensate for the feeling of cornering despite the degree of banking on the Shinkansen lines (interesting when you have the rare experience of being slowed to nearly a stand on such a heavily banked curve), although i have always found Shinkansen trains to ride nicely even in corners (mostly due to having a dedicated network) my experience being limited to the '0' series (which was only called that later and now out of traffic), 300 (now out of traffic), 500 (now operating Kodama services), 700 and N700 series.

As ever, tilt will affect people differently and some people will feel sickness whatever degree of tilt there is and sometimes with no tilt at all. There have frequently been complaints from passengers of sickness due to tilting when tilt has been locked out and on Voyagers which, as Swaldman correctly said, don't even have tilt equipment. We are, after all, all different.

 

[GrimShady]

My memory from the time was that BR InterCity eventually decided that the economics of 140 mph operation didn't stack up - increased maintenance costs of track and rolling stock, increased energy costs and reduced line capacity. Also possibly having to install some form of cab signalling or at least proper automatic train stops (e.g. the equivalent of TPWS) before the Railway Inspectorate might allow day-to-day 140 mph operation (the flashing greens north of Peterborough were intended just for testing purposes I think).

It was similar with APT-P, they realised that running the train with tilt and at high speed was going to to cost them on train maintenance which was one of the reason the business case for APT changed.

You are correct the flashing green was solely for testing purposes.

 

[whhistle]

I thought the Voyagers (as opposed to Super Voyagers) didn't tilt at all? Or am I wrong?

That's correct.

Voyagers = Non-tilt.
Super Voyagers = Tilt.

Cross Country's Super Voyagers (IE: 221s) have had their tilt gubbins mechanically removed/disabled so their Super Voyagers don't tilt.

 

[GrimShady]

https://www.apt-p.com/APTConfigurations.htm

Good site that, there's also reference to a diesel APT at some stage. I also remember hearing rumours of a proposed APT-Motorail. No idea if any of it was true.

 

[JohnElliott]

https://www.apt-p.com/APTConfigurations.htm

Good site that, there's also reference to a diesel APT at some stage. I also remember hearing rumours of a proposed APT-Motorail. No idea if any of it was true.

And "APT for Southern Region" - a dual-voltage version for the Euston-Victoria crossrail?

 

[GrimShady]

And "APT for Southern Region" - a dual-voltage version for the Euston-Victoria crossrail?

Looks like it. See here for an illustration of APT at Croydon. https://www.londonreconnections.com/2011/what-if-crossrail-1980/