Pendolino speed limit on non-EPS routes

[najaB]

It has been posted on another thread (can't remember which one at the moment) that Class 390s are limited to 110mph when not on TASS-equipped routes. As I understand it, this is because they aren't allowed to run any faster with tilt disabled.

Why do Pendolinos have this limitation but Voyagers don't? Is it because they were designed as 'captive' stock for the WCML? Is it an artificial limit that exists purely because there's no reason not to or is it something fundamental about the design that makes non-tilt 125mph operation unsafe/undesirable?

 

[55z]

All tilt units (including 221) with tilt disabled on just one coach are restricted to the non EPS speed i.e. the lower speed limit whatever that limit is with a maximum speed of 110 mph. If normal speed limit is 80 mph and EPS (tilt) is 90 mph then with tilt disabled then the speed limit of 390 & 221 is 80 mph. The cross Country 221's are now non tilt as the tilt mechanism has been removed or disabled to improve reliability only West Coast 221's can tilt (as well as 390's)

 

[najaB]

All tilt units (including 221) with tilt disabled on just one coach are restricted to the non EPS speed i.e. the lower speed limit whatever that limit is with a maximum speed of 110 mph.

So if XC was to re-activate the tilting equipment on their 221's they would be limited to 110mph on the routes that they currently run at 125mph? Is this to protect against uncommanded tilt?

 

[Domh245]

All tilt units (including 221) with tilt disabled on just one coach are restricted to the non EPS speed i.e. the lower speed limit whatever that limit is with a maximum speed of 110 mph. If normal speed limit is 80 mph and EPS (tilt) is 90 mph then with tilt disabled then the speed limit of 390 & 221 is 80 mph. The cross Country 221's are now non tilt as the tilt mechanism has been removed or disabled to improve reliability only West Coast 221's can tilt (as well as 390's)

I think najaB's question was why would a pendolino be (supposedly) limited to 110mph on the ECML, despite the fact that both the train, and the tracks, are cleared for 125mph operation.

I would guess it is a paperwork issue. The only 125mph track that they encounter is EPS track (AFAIK) and the highest non-EPS track is 110. Therefore, even though they could operate at 125mph on non-EPS track, they have only been cleared for 110mph

 

[Minilad]

Wolverhampton to Stafford is 125 non EPS and there is always some debate about 390 speeds along this section

 

[najaB]

I think najaB's question was why would a pendolino be (supposedly) limited to 110mph on the ECML, despite the fact that both the train, and the tracks, are cleared for 125mph operation.

Is it something physical (e.g. protection from uncommanded tilt) or is it just that there's never been a need so the paperwork's never been done?

 

[Domh245]

Is it something physical (e.g. protection from uncommanded tilt) or is it just that there's never been a need so the paperwork's never been done?

I would have hoped the latter! A system should fail safe, so a Pendolino should be designed that if it doesn't receive any TASS signals, it actively prevents tilt.

Then again, it may be something to do with gauging. Pendolino intermediate cars are 23.9m, vice the mk4's 23.4 over the couplings. That may cause issues with the kinematic envelope and structure clearances, but that *should* just be a paperwork issue again, unless there are some really tight clearances.

 

[sprinterguy]

On the thread on here that discussed the testing of a Pendolino over the length of the ECML, between Edinburgh to Kings Cross, in March 2012, it was suggested that the runs were timed for 125mph with tilt disabled.

Other sources suggest it was limited to 110mph though and the schedules for these runs were lengthened by extended layovers en route, so it is difficult to confirm.

 

[neilb62]

Wolverhampton to Stafford is 125 non EPS and there is always some debate about 390 speeds along this section

There is no debate at all. Non-tilt 390's 90 mph along this stretch. This being the non-eps line speed. When TASS/Tilt is inactive or isolated or on a non-Tass fitted line 390 obeys the Normal line speed. If the train exceeds 113mph non-tilt the Driver will get an over speed warning on the TMS display as well as an audible alarm.

 

[edwin_m]

There is no debate at all. Non-tilt 390's 90 mph along this stretch. This being the non-eps line speed. When TASS/Tilt is inactive or isolated or on a non-Tass fitted line 390 obeys the Normal line speed. If the train exceeds 113mph non-tilt the Driver will get an over speed warning on the TMS display as well as an audible alarm.

But if the non-EPS speed is 125 as suggested, then can't 390s at least do 110?

 

[kieron]

Wolverhampton to Stafford is 125 non EPS and there is always some debate about 390 speeds along this section

According to the SA, it's 125mph for EPS or MU trains, 90 for anything else. 185s and 390s don't benefit from MU differential speeds for some reason, but 220s and 221s do.

Incidentally, it lists a section near Congleton with a 115mph MU speed. Would a Virgin 221 be allowed to travel at this speed if tilting had been turned off on it for whatever reason?

 

[neilb62]

But if the non-EPS speed is 125 as suggested, then can't 390s at least do 110?

The non-EPS speed is 90, the 125 is a MU speed, something different that doesn't apply to 390's.
IIRC 390 has to adhere to 'Table A' speeds due to the track forces produced in non-tilt mode.
--- old post above --- --- new post below ---

According to the SA, it's 125mph for EPS or MU trains, 90 for anything else. 185s and 390s don't benefit from MU differential speeds for some reason, but 220s and 221s do.

Incidentally, it lists a section near Congleton with a 115mph MU speed. Would a Virgin 221 be allowed to travel at this speed if tilting had been turned off on it for whatever reason?

Yes, a XC 220/1 too...

 

[TheKnightWho]

I would have hoped the latter! A system should fail safe, so a Pendolino should be designed that if it doesn't receive any TASS signals, it actively prevents tilt.

Then again, it may be something to do with gauging. Pendolino intermediate cars are 23.9m, vice the mk4's 23.4 over the couplings. That may cause issues with the kinematic envelope and structure clearances, but that *should* just be a paperwork issue again, unless there are some really tight clearances.

Considering the ECML has been cleared for 26m IEPs now, this shouldn't be an issue.

 

[najaB]

I would have hoped the latter! A system should fail safe, so a Pendolino should be designed that if it doesn't receive any TASS signals, it actively prevents tilt.

Oh yes, it goes without saying that systems should fail safe. I'm just trying to figure out why they can go faster than non-tilt trains on TASS-fitted tracks but are limited to a lower speed on a track where non-tilt trains can do 125mph. And in the case of 221s - with tilt physically deactivated they can do 125mph, with it activated but turned off it can only do 110mph.

 

[Jonfun]

Oh yes, it goes without saying that systems should fail safe. I'm just trying to figure out why they can go faster than non-tilt trains on TASS-fitted tracks but are limited to a lower speed on a track that where non-tilt trains can do 125mph. And in the case of 221s with tilt deactivated can do 125mph, with it activated but turned off it can only do 110mph.

Eh? A 221 can do 125mph non-tilt.

Edit: theoretically, subject to appropriate speed restrictions due to linespeeds/equipment failure/etc etc...

 

[najaB]

Eh? A 221 can do 125mph non-tilt.

Edit: theoretically, subject to appropriate speed restrictions due to linespeeds/equipment failure/etc etc...

I know they're capable of 125, but according to 55z's post above they are limited to the lower of the non-EPS speed or 110mph with tilt disabled (rather than deactivated).

 

[neilb62]

I know they're capable of 125, but according to 55z's post above they are limited to the lower of the non-EPS speed or 110mph with tilt disabled (rather than deactivated).

That doesn't mean he's right....

221's either tilt or non-tilt can do MU speed if it's there. So can 220's for that matter.

 

[najaB]

221's either tilt or non-tilt can do MU speed if it's there. So can 220's for that matter.

Which brings us back to the original question: ECML, non-tilt train can do 125mph, Pendolino is limited to 110mph - what's the actual reason?

 

[Philip Phlopp]

Which brings us back to the original question: ECML, non-tilt train can do 125mph, Pendolino is limited to 110mph - what's the actual reason?

Axle loadings, isn't it, same as why a Class 185 isn't permitted to do MU differential speeds.

It becomes a paperwork issue when you want to run a Class 390 on a route with a fixed 125mph speed limit, say around Slough (first place I could think of in a Sectional Appendix I have open), but on the WCML, as there's no 125mph speed limit, just 125mph differentials for MUs and for EPS stock, it's a moot point.

 

[najaB]

Axle loadings, isn't it, same as why a Class 185 isn't permitted to do MU differential speeds.

Could be. Though I would've thought they were a lightweight given that they are designed for 140mph.

 

[Starmill]

There's a lot of different confusing use of terminology in this thread, particularly regarding 'disabled' and 'deactivated'.

 

[neilb62]

Could be. Though I would've thought they were a lightweight given that they are designed for 140mph.

It is to do with axle loadings and track force. They are far from lightweight an 11 car 390 loaded is around 600 tons, possibly more. It's also to do with the way the tilt system and suspension is set up. A 221 is a 125mph train by default. A 390 is a 110 mph train that can do up to 140 mph in tilt mode.

 

[najaB]

There's a lot of different confusing use of terminology in this thread, particularly regarding 'disabled' and 'deactivated'.

I've tried to use 'deactivated' to mean incapable of tilt due to a physical modification (e.g the equipment has been removed), and 'disabled' to mean capable of tilt but not using that capability (e.g. the tilt switch is in the 'off' position).
--- old post above --- --- new post below ---

A 221 is a 125mph train by default. A 390 is a 110 mph train that can do up to 140 mph in tilt mode.

One more reason to dislike Pendolino's, they've been faking it all along!

 

[Kentish Paul]

Surely its more than axle loading?

An 11 coach Pendolino is 600 tons. This is 54 tons per coach or 14 tons per axle.
OK some coaches will be heavier than others but I cannot believe the axle load on a particular 390 coach exceeds the 20 tons per axle of a class 91.

 

[driver_m]

I know they're capable of 125, but according to 55z's post above they are limited to the lower of the non-EPS speed or 110mph with tilt disabled (rather than deactivated).

As Neil has already said. A 221 can do 125 max regardless of whether it is tilting or not. 55z is wrong. Simple as.
A long time ago now, but a 115 ps limit near Macclesfield was supposedly able to let a pendo not tilting to do 115, however following some questioning of this a clarification came out that if the pendo hadn't got TASS active at that time it could do no more than 110.

If memory serves me correctly an empty 11 car pendo weighs 570t.

 

[Erniescooper]

The ECML test run was timed at and ran at 125mph. There is a combination of cab isolations that allows you to do this. Pendolino is route cleared for most of the East Coast at the same speed as other stock but obviously it isn't allowed to tilt.

 

[driver_m]

The ECML test run was timed at and ran at 125mph. There is a combination of cab isolations that allows you to do this. Pendolino is route cleared for most of the East Coast at the same speed as other stock but obviously it allowed to tilt.

What does that last bit mean? The set doing the test run didn't tilt because there weren't any balises. Whoever is in charge of the ECML route would have agreed on what the set could do.

The TMS squawks at us for doing over 113 non tilt but doesn't throw the brake on, that's for us to deal with so what's this isolation that stops this?

 

[Philip Phlopp]

What does that last bit mean? The set doing the test run didn't tilt because there weren't any balises. Whoever is in charge of the ECML route would have agreed on what the set could do.

The TMS squawks at us for doing over 113 non tilt but doesn't throw the brake on, that's for us to deal with so what's this isolation that stops this?

I thought the run on the ECML had people from Alstom with laptops present, the set was loaded with a different version of the TMS which disabled tilt completely and enabled 125mph operation. I didn't think there was isolations and things in the conventional sense, it was all done in the software code.

 

[driver_m]

I thought the run on the ECML had people from Alstom with laptops present, the set was loaded with a different version of the TMS which disabled tilt completely and enabled 125mph operation. I didn't think there was isolations and things in the conventional sense, it was all done in the software code.

Yeah there was all kinds of monitoring stuff aboard from what we were told, we knew it was a one off run which has its own agreements, I was just referring to the isolation in particular as it isn't something that would happen normally. Any isolating to tilt that we do immediately makes the set 110max and the 113 max TMS message applies whether tilt has been lost temporarily or permanently

 

[455driver]

The cross Country 221's are now non tilt as the tilt mechanism has been disabled to reduce track access payments, only West Coast 221's can tilt (as well as 390's)

Slight edit made for clarity!