Class 455 incident at Waterloo Sunday evening

[cjmillsnun]

Why would i need to quote your whole post? You were stating there are delays in the system which i wanted you to explain.

I can't explain why it seems like the leading unit pulls away from the trailing unit because the fact is it doesn't. A signal is passed down the train wire which will demand power from all engines / transmissions or motors simultaneously.

Why is it then that whichever end I drive from the leading unit always cammes up faster than the rear unit. When I change ends its the same thing, the front unit (which was the rear unit) now takes the lead and cammes up quicker!

I'm assuming NFF may be one of the maintenance guys, and I'm sure that in theory he's correct that a signal is sent to all traction motors simultaneously.

However I'd be inclined to believe 455driver as someone with extensive experience driving the units day in day out. Also the seat of the pants experience I have as a passenger tells me that the 455 isn't the only unit that behaves like that.

 

[A-driver]

So that's why you get that sharp lurch just as you start motoring? I was on a 455 twice on Saturday and noticed it at every pullaway, plus the jolt as you suddenly stop motoring :P. Don't mind these two as much but when acceleration is not smooth it really bugs me for some reason

I think the sharp lurch you refer to is the motors taking power as they work on a less than subtle camshaft. 313s do the same thing.

 

[Monty]

Force an early takeover of services by TfL, because they'd be much better than any TOC. On arrival, they'd say LO, LO, LO...

Best post ever, period.

 

[455driver]

So that's why you get that sharp lurch just as you start motoring? I was on a 455 twice on Saturday and noticed it at every pullaway, plus the jolt as you suddenly stop motoring :P. Don't mind these two as much but when acceleration is not smooth it really bugs me for some reason

No excuse for the jolt when shutting off, the driver should have put the power handle into shunt (to lock the camshaft) about 10mph below the target speed and then there wouldnt have been a jolt at all.
If the 2 units dont like each other then I would hand notch it to stop the jolting.

It sounds as if the driver didnt know how to drive them properly or just couldnt be bothered.

 

[JB25]

No excuse for the jolt when shutting off, the driver should have put the power handle into shunt (to lock the camshaft) about 10mph below the target speed and then there wouldnt have been a jolt at all.
If the 2 units dont like each other then I would hand notch it to stop the jolting.

It sounds as if the driver didnt know how to drive them properly or just couldnt be bothered.

I know we drive for different companies, but never heard that before I have to be honest. We are just told to go back to Shunt, wait a second or two then shut off.

 

[plastictaffy]

We had a seperation issue about a month ago - 2 321's came apart on departure from Euston. As far as I know, the incident was dealt with in-house.

 

[455driver]

I know we drive for different companies, but never heard that before I have to be honest. We are just told to go back to Shunt, wait a second or two then shut off.

It depends on the speed, I am assuming that as the jolt is quite severe on shutting off that the speed is quite low(less than 30ish) so shutting off my way would work best.

Once the train is into weakfield (45ish) then yours is best, in between its a bit of both.

 

[No Fault Found]

Why is it then that whichever end I drive from the leading unit always cammes up faster than the rear unit. When I change ends its the same thing, the front unit (which was the rear unit) now takes the lead and cammes up quicker!

Ok. From a technical point of view, that can't physically happen. Genuine question now.

How, when you're driving two 150-ton units coupled together from the leading end, can you tell that one unit is pulling away from the other?

 

[Goldfish62]

Why is it then that whichever end I drive from the leading unit always cammes up faster than the rear unit. When I change ends its the same thing, the front unit (which was the rear unit) now takes the lead and cammes up quicker!

I wonder if that'll still be the case when they get their new traction.

 

[455driver]

Ok. From a technical point of view, that can't physically happen. Genuine question now.

How, when you're driving two 150-ton units coupled together from the leading end, can you tell that one unit is pulling away from the other?

Because when I was a guard I used to watch the gangway connections and the front unit always pulled away from the rear unit with the rear unit camming up a second or 2 later (I look for these types of things, sad really) and nobody could answer why except for the fact that its always like that.

The only time I have seen it compress is when the front unit was dead and so being pushed by the rear unit.
--- old post above --- --- new post below ---

I wonder if that'll still be the case when they get their new traction.

I hope not as the power delivery should be seamless.

 

[BestWestern]

What on earth were the BTP expected to do about it!?

Assist with a detrainment, deal with any annoyed passengers that their train has been cancelled, provide support to the rail staff dealing with it, quickly make sure that it hasn't happened due to criminal activity.

You lot complain that the BTP are nowhere to be seen most of the time, and then complain when they do turn up!

I have no objection to the BTP wandering over for a look, but I'm a tad baffled why any staff would feel the need to summon them for this. I'm sure SWT have plenty of staff about to deal with detraining in a platform at Waterloo, and the incident itself certainly isn't one that needs their investigation. Still, reassures the punters I suppose!

 

[jon91]

It might only be a fraction of a second's worth of a delay but its enough to create that difference between two units when using a mechanical control for switching out resistances i.e. a camshaft.

Then you have other factors like variation in condition between individual units to think of...

 

[Pumbaa]

I have no objection to the BTP wandering over for a look, but I'm a tad baffled why any staff would feel the need to summon them for this. I'm sure SWT have plenty of staff about to deal with detraining in a platform at Waterloo, and the incident itself certainly isn't one that needs their investigation. Still, reassures the punters I suppose!

I doubt they were summoned - they'd have been on Waterloo concourse due to the busy crowds from discount ticket sale and Twickenham match.

 

[badassunicorn]

You know, I reckon this "delay" thingy could be attributed to these units having only one motor coach each. I have often found the same, where there is a lurch upon starting, not dissimilar to when a loco tugs or pushes a rake of coaches, but if you sit in the motor coach you don't seem to get it. So, drivers should sit in the PMSO coach instead of the cabs. Done.

 

[Nicks]

I saw the whole thing and the police were most definitely called - the BTP police car was met and the policeman escorted to the incident - no interest was taken in the detraining of the passengers either - just a lot of looking at the track between the units. I assume this incident has led to the short formations all week which has been a right pain especially at peak!

 

[TEW]

The short formations have been going on for a while, but there's probably been a few more this week.

 

[dewsnapsliding]

Ok. From a technical point of view, that can't physically happen. Genuine question now.

How, when you're driving two 150-ton units coupled together from the leading end, can you tell that one unit is pulling away from the other?

Why the need for any mechanical coupling then if the through pipes/electrics operate both exactly the same, at exactly the same time?

Same genuine question.

 

[al.currie93]

If the 2 units dont like each other then I would hand notch it to stop the jolting.

I quite like that idea of two 455s not liking each other; it's as if these machines still have a bit of the old railway vehicle personality that all locomotives and units used to have but is so rare these days I like these units even more now haha!

Sorry bit off-topic :P maybe I should make a new thread for locomotives and units that still have personality and character :P

 

[455driver]

Some units will run around the cam faster than others and so can jolt quite a bit when setting off, hence not liking each other.

 

[No Fault Found]

Why the need for any mechanical coupling then if the through pipes/electrics operate both exactly the same, at exactly the same time?

Same genuine question.

In case one engine is isolated? In case one unit has a dragging brake? Many reasons. And to not have a mechanical coupling would be pretty stupid wouldn't it.

I didn't say both units would react at exactly the same at exactly the same time, infact what i was saying is quite the opposite. One unit will pull (push) away quicker than the other. On one journey that may be the leading unit but when you change ends that will then be the trailing unit so you should have that unit pushing the now leading unit.
--- old post above --- --- new post below ---

Some units will run around the cam faster than others and so can jolt quite a bit when setting off, hence not liking each other.

Apologies if some of my responses were a bit sarchastic. I must also admit, i've never worked on a 455 so am not 100% familiar with the cam setup so maybe you are right with 455. I was referring to other types of traction that i do / have worked on where there should be no delays in vehicles getting a demand for power.

 

[user15681]

I'd like to hope it was coincidental that a similar event should occur this evening elsewhere

In all reality, how often does this happen? Even though events like the one at Waterloo were fairly safe and dealt with appropriately, I'd like to hope it wasn't often.

 

[hedpe]

As has already been written, the separation of two units would pull out the electrical control jumper cables. You'd lose brake continuity/interlock. Under these conditions, power cant be applied to the motors. Additionally, the 455's do not have corridor connections between units. The danger to those onboard when separation occurs between a pair of units pulling out of station is negligible. The type of coupler used on these units is no longer fitted to new trains as far as i am aware. I think it was developed over in the USA and is used substantially across different classes of EMU dating from 70's up til late 90's/early 00's?, however it predates the new 'dellner' type coupler of which i have no experience on. I can only imagine that the knuckle on one of the units failed, not locking correctly in the 'couple' position. There are visual indications that indicate the coupler has engaged (ie the 'telltail')

 

[455driver]

I Apologies if some of my responses were a bit sarchastic.

Not at all, I am fine with it (hell, I am all for a bit of sarcasm ), nothing wrong with a 'robust' debate anyway!

I must also admit, i've never worked on a 455 so am not 100% familiar with the cam setup so maybe you are right with 455. I was referring to other types of traction that i do / have worked on where there should be no delays in vehicles getting a demand for power.

The 455s are olde* technology by modern standards and probably have more foibles than any other train still in front line service.

*E on the end intended.

 

[cjmillsnun]

As has already been written, the separation of two units would pull out the electrical control jumper cables. You'd lose brake continuity/interlock. Under these conditions, power cant be applied to the motors. Additionally, the 455's do not have corridor connections between units. The danger to those onboard when separation occurs between a pair of units pulling out of station is negligible. The type of coupler used on these units is no longer fitted to new trains as far as i am aware. I think it was developed over in the USA and is used substantially across different classes of EMU dating from 70's up til late 90's/early 00's?, however it predates the new 'dellner' type coupler of which i have no experience on. I can only imagine that the knuckle on one of the units failed, not locking correctly in the 'couple' position. There are visual indications that indicate the coupler has engaged (ie the 'telltail')

Definitely a corridor connection on SWT 455s. I believe it's staff use only, but it's there!

EDIT changed photo for a smaller one (pic from Railway Gazette.com) http://www.railwaygazette.com/news/...trains-emus-to-get-ac-traction-equipment.html

 

[90019]

He's thinking of the Southern 455s, which had the corridor connections removed.

 

[A-driver]

I'm inly willing to divulge what was on twitter as the other stuff I have heard at work is all part of ongoing investigations but a set of 317s came apart just south of Hitchin in yesterday's evening rush hour heading to Cambridge.

As I say, that's all I will say at present as that was on twitter.

 

[TDK]

the 455's use pipes and jumper cables that are separate to the coupler face. If two units separated in service through mechanical failure of the knuckle, im not sure how immediately obvious it would be until the units separated far enough for the air lines and jumper cables to de-attach.

If the coupling is divided I think that this will in turn break train wire 4 that will apply the brakes on both units immediately as when I did my traction you would never get the brakes off if the couple button was pressed in a single unit. Whether train wire 4 is connected via the jumper I am sure 455 driver will know the answer to this one. All units, not only 455's have their differences and DMU's such as 15x's are very different where each individual coach is different with the voith gearbox going to fluid coupling at different speeds and each individual coach taking up power from idle at slightly different times. With the 455's in multiple the front unit will normally always move slightly before the rear and this as I recall is down to the control circuits taking time to reach the rear unit.

 

[455driver]

All electrical connections are through the jumper cable with the main res hose taking care of the air supply, the coupler is purely a mechanical connection.

Only when the main res pipe pulls apart will the driver be aware of anything untoward which normally happens within a couple of feet, the hoses are not very long. The guard (if in the middle cab) will be aware of it somewhat quicker as they watch the front unit pull away!

 

[gage75]

Slightly off topic, but has this sort of thing ever happened on LUL stock??

 

[cjmillsnun]

He's thinking of the Southern 455s, which had the corridor connections removed.

Every time I look at a SN 455 I do wonder what possessed them to do that. There must've been a better way they could've incorporated the air con unit, and agreed he probably was thinking of the SN 455s. However with the incident happening at WAT, it will be SWT stock that was affected.