Buckeye couplers, tell tale pin on SR MUs

[bronzeonion]

Evening,

Just a thought, with the tell tale pins provided on the Buckeye couplers of most SR MU stock is it still a requirement to do a pull away test?

Bit random, cheers!

 

[ExRes]

I would hope that it's still a requirement to do a pull-away test after coupling on every type of stock in existence

I know from experience that even on such 'modern' and 'sophisticated' stock as 222s it's quite possible for the physical connection to fail during the test, whatever, for the sake of a few seconds it's better to be safe than sorry

 

[Domh245]

I'd imagine so. Whilst the telltale pin may be showing that the coupler, it could be possible that when the train accelerates or decelerates, the knuckle could open, or even shear off. As ExRes, it is better to be safe than sorry, pulling backwards and stopping only takes about 10 seconds (as a pessimistic guesstimate), and a 1/4 minute padding in the timetable is going to be better than a runaway train hurtling away on a mainline, wreaking havoc, and bringing about company-wrecking fines.

 

[millemille]

They're tightlock couplers, not buckeye, on Southeastern stock not equipped with Dellner couplers.

Tell tales generally aren't used as the primary check of coupling function as they aren't readily visible from the platform. There are painted lines on the uncoupling cylinder linkage and rotor shaft which are easy to check, if coupled correctly with the drop lock all the way down the painted lines will align.

Yes, pull away tests are still carried out.

Comments about "runaway trains hurtling down the mainline" show a fundamental lack of understanding of rolling stock. A breakaway will cause the brakes to apply on all vehicles. From 1st hand experience of attending and investigating inter-unit, and inter-vehicle, breakaway's the parts of the formation generally come to a stop within no more than a hundred feet of each other.

The other point to note is that if the tell tales are showing correctly or the painted lines on the rotor shaft are aligned it is not possible for the pull away test to fail. The pull away test is used as the primary check to, hopefully, eliminate human error when carrying out a visual check that can be open to error/interpretation.

There have been occasions when tightlock coupler's have failed and the knuckles opened, despite passing a pull away test when last coupled, due to problems with the anti-creep mechanism, allowing the lock to lift due to vibration whilst in service. This failure mode isn't detectable/preventable except on maintenance.

 

[ac6000cw]

I would hope that it's still a requirement to do a pull-away test after coupling on every type of stock in existence

I know from experience that even on such 'modern' and 'sophisticated' stock as 222s it's quite possible for the physical connection to fail during the test, whatever, for the sake of a few seconds it's better to be safe than sorry

I think there was an incident a few years ago where a two 365's parted company at speed on the GN mainline (this initiates an emergency brake application of course - no 'runaway train hurtling away on a mainline, wreaking havoc', that's why train braking systems are required to be fail-safe).

They're always very careful about coupling Kings Lynn portions on at Cambridge....sometimes a double pull-away test just to make sure.

 

[westcoaster]

I think there was an incident a few years ago where a two 365's parted company at speed on the GN mainline (this initiates an emergency brake application of course - no 'runaway train hurtling away on a mainline, wreaking havoc', that's why train braking systems are required to be fail-safe).

They're always very careful about coupling Kings Lynn portions on at Cambridge....sometimes a double pull-away test just to make sure.

FCC drivers have to do 2 pullaway tests for 5 seconds. On all stock.

 

[ExRes]

I did forget to mention earlier that with the advent of the data recorder, call it what you will, any failure to do a proper pull away test would stick out like a sore thumb on a download, another reason for using those few seconds wisely

 

[badassunicorn]

Also, what's the general consensus on placing the unit to be coupled onto into Emergency? I was taught to always place the unit to be coupled onto into emergency as a safeguard (except desiros), and then check the butterflies and pull away test etc etc, do other areas do this practice?

 

[KA4C]

Evening,

Just a thought, with the tell tale pins provided on the Buckeye couplers of most SR MU stock is it still a requirement to do a pull away test?

Bit random, cheers!

On the classic stock (400 series, 200 series) which had buckeyes, yes you always do a pull away

As has been said, it the stock was gangway fitted, you couldn't see the pin from the platform

Pins used to stick up on the buckeye grease, used to knock em down with a paddle

 

[bronzeonion]

They're tightlock couplers, not buckeye, on Southeastern stock not equipped with Dellner couplers.

Tell tales generally aren't used as the primary check of coupling function as they aren't readily visible from the platform. There are painted lines on the uncoupling cylinder linkage and rotor shaft which are easy to check, if coupled correctly with the drop lock all the way down the painted lines will align.

Yes, pull away tests are still carried out.

Comments about "runaway trains hurtling down the mainline" show a fundamental lack of understanding of rolling stock. A breakaway will cause the brakes to apply on all vehicles. From 1st hand experience of attending and investigating inter-unit, and inter-vehicle, breakaway's the parts of the formation generally come to a stop within no more than a hundred feet of each other.

The other point to note is that if the tell tales are showing correctly or the painted lines on the rotor shaft are aligned it is not possible for the pull away test to fail. The pull away test is used as the primary check to, hopefully, eliminate human error when carrying out a visual check that can be open to error/interpretation.

There have been occasions when tightlock coupler's have failed and the knuckles opened, despite passing a pull away test when last coupled, due to problems with the anti-creep mechanism, allowing the lock to lift due to vibration whilst in service. This failure mode isn't detectable/preventable except on maintenance.

Sorry I should have made it clearer, I meant the MK1 based which do/did use buckeye couplers! Interesting to learn about the procedures on more modern stock though.
--- old post above --- --- new post below ---

On the classic stock (400 series, 200 series) which had buckeyes, yes you always do a pull away

As has been said, it the stock was gangway fitted, you couldn't see the pin from the platform

Pins used to stick up on the buckeye grease, used to knock em down with a paddle

Thank you

 

[swt_passenger]

I would hope that it's still a requirement to do a pull-away test after coupling on every type of stock in existence

From a passenger perspective I've not seen any sort of pull-away test happening on an SWT Desiro. That's not to say coupling integrity isn't being checked somehow, but there's certainly not the sort of 'tug of war' you see with their DMUs when joining...

 

[ExRes]

From a passenger perspective I've not seen any sort of pull-away test happening on an SWT Desiro. That's not to say coupling integrity isn't being checked somehow, but there's certainly not the sort of 'tug of war' you see with their DMUs when joining...

I won't disagree as I've never driven one, but I find it deeply worrying if these units are being attached and reliance is solely based on a computer system rather than a physical test, that's a recipe for disaster, well hopefully not a disaster of course, but some very eggy faces at least

I do bump into a former SWT instructor at times, i'll be interested to ask him what system is in place

 

[A-driver]

FCC drivers have to do 2 pullaway tests for 5 seconds. On all stock.

Only on TL. No such requirement for GN drivers. We just do 1 pull away test.


Re the comments about 365s, there was a phase of them coming apart but they have since been modified. They were coming apart as from a platform it is almost impossible to see the yellow pins as the buffers get in the way. This caused problems when attaching in platforms like kings cross 9,10,11 or carriage sidings like letchworth as curves are notoriously bad places to attach units. As drivers couldn't fully see the pins they were breaking apart. Now a pin has been added at the top of the tightlock and if that is aligned vertically then it is coupled properly. Since then they have had no issues with breakaways (touch wood).

The more worrying incident was a few months back on the down slow approaching hitchin in the evening peak when a 317 broke apart. Could have bee nasty as they have a passenger walk through so, despite the brakes applying on both units, someone could have potentially needed up under the rear unit. Although pins and pull away tests had nothing to do with that as it turned out to be a fault with the tightlock and there are still a couple of 317s running around with "do not couple this end" cards displayed in the cabs.

 

[A-driver]

From a passenger perspective I've not seen any sort of pull-away test happening on an SWT Desiro. That's not to say coupling integrity isn't being checked somehow, but there's certainly not the sort of 'tug of war' you see with their DMUs when joining...

I doubt you would be able to tell if a pull away test was being done as a passenger anyway as on modern units there is very little movement.

 

[Bigfoot]

Once the desiros are coupled the cab becomes 'dead' apart from the emergency stop and uncouple button. There is a mechanically coupled only indicator but that is only for when there is an elecrical block issue.

 

[A-driver]

Once the desiros are coupled the cab becomes 'dead' apart from the emergency stop and uncouple button. There is a mechanically coupled only indicator but that is only for when there is an elecrical block issue.

That is quite surprising. Is it possible mechanically only couple a desiro then and driver from other than the leading cab?

 

[ExRes]

That is quite surprising. Is it possible mechanically only couple a desiro then and driver from other than the leading cab?

I would hope not, surely only the unit the driver is coupling from is under his/her control until electrical connection is made, the other units could not have their brakes released until then

 

[SpacePhoenix]

Once the desiros are coupled the cab becomes 'dead' apart from the emergency stop and uncouple button. There is a mechanically coupled only indicator but that is only for when there is an elecrical block issue.

When two Desiros couple, from vids on Youtube, do all headlights and rear lights get automatically turned off for the cabs that have just coupled?

 

[user15681]

I've not been a good omen for couplings this past week. Saw units move during a pull away test, a unit with a very wonky coupler and non multi sticker and two units come apart this evening.

 

[A-driver]

I would hope not, surely only the unit the driver is coupling from is under his/her control until electrical connection is made, the other units could not have their brakes released until then

Then how do you move a failed train?

In normal service you would need an electrical connection but it is possible in most units to mechanically couple to a failed unit, isolate the brakes on the failed unit and then drag or push the failed unit clear. Obviously not possibly on a desiro if the cab automatically shuts down after being mechanically attached.

 

[swt_passenger]

When two Desiros couple, from vids on Youtube, do all headlights and rear lights get automatically turned off for the cabs that have just coupled?

I'd think so, they seem to go out at the same stage of the connection every time, and on both units simultaneously. They also come on together when splitting.

 

[ExRes]

Then how do you move a failed train?

In normal service you would need an electrical connection but it is possible in most units to mechanically couple to a failed unit, isolate the brakes on the failed unit and then drag or push the failed unit clear. Obviously not possibly on a desiro if the cab automatically shuts down after being mechanically attached.

I think you've answered the question yourself, if the rescuing unit can't override the reason for failure then the brakes on the failure are isolated or bypassed so that the train can then be moved

 

[cjmillsnun]

I think you've answered the question yourself, if the rescuing unit can't override the reason for failure then the brakes on the failure are isolated or bypassed so that the train can then be moved

And if it is an electrical fault that affects the assisting unit when coupled up?

 

[bronzeonion]

Wait, with all this talk about electrical connections etc, does this mean you need one to get a brake release when coupling onto an electrically broken or dead unit or is an air connection sufficient?

 

[A-driver]

I think you've answered the question yourself, if the rescuing unit can't override the reason for failure then the brakes on the failure are isolated or bypassed so that the train can then be moved

What I was asking is that if the cab goes dead as soon as you mechanically couple up then brakes isolated or not, you won't be able to drive from a middle cab, this is an option on all other stock and is used with certain unit failiures.

 

[Bigfoot]

There was a failed 450 that hit a tree at christmas that was assisted in the rear then driven from the rear cab in reverse from Weybridge to Waterloo then into clapham yard. Obviously with a competent person at the front relaying instruction to the driver at the rear...

 

[A-driver]

There was a failed 450 that hit a tree at christmas that was assisted in the rear then driven from the rear cab in reverse from Weybridge to Waterloo then into clapham yard. Obviously with a competent person at the front relaying instruction to the driver at the rear...

So in that case it couldn't have been driven from an intermediate cab, only the back cab. That was my question as with all the stock I sign you could drive from any other cab.