what happens if a tram breaks down

[Mothball]

Hi
I use the metrolink a lot and a couple days ago i was on a tram when the driver said we had to get off at abraham moss as the tram had a problem
I guess thw problem was not very serious as the tram drove away when we get off but what happens if a tram cant move anymore??
I have seen the diesel train at thdepot by queens road station so does that help or can one m5000 tram pull another one along if one was broken thanks

 

[DanNCL]

In the specific case of the M5000s they can be rescued by another M5000 relatively easily using the standard couplers used for multiple working. 1027 (the diesel vehicle you’re referring to) can also be used if required.

Most other trams in the UK don’t have automatic couplers so the process to rescue them with another tram is a bit more complex.

 

[Mothball]

In the specific case of the M5000s they can be rescued by another M5000 relatively easily using the standard couplers used for multiple working. 1027 (the diesel vehicle you’re referring to) can also be used if required.

Most other trams in the UK don’t have automatic couplers so the process to rescue them with another tram is a bit more complex.

Hi
so when one m5000 is pulling a broken one does the good tram stilll drive the broken tram like they do when driving normally
can yhe 1027 alsp drive the broken tram thank you again

 

[scrapy]

Hi
so when one m5000 is pulling a broken one does the good tram stilll drive the broken tram like they do when driving normally
can yhe 1027 alsp drive the broken tram thank you again

It will all depend on what the fault is.

 

[JD2168]

If a Tram breaks down on the Sheffield Supertram another Tram comes along & tows it to the depot.

 

[Vespa]

In the worst case scenario they can call out a class 37 thunderbird train to tow it, now that would be a sight to see that in the main street of Manchester or Sheffield

On a serious note:
There will be a contingency of towing it out of service, if necessary utilising single workings or parking it in a siding if you can't tow it back to base, the couplers will allow dual control.

 

[Mcr Warrior]

@507 001 should be well placed to further advise with good authority.

 

[AndrewE]

So can the following service buffer up and propel the dead one - driven from the front cab? Presumably the passengers of both trams get turfed off...
Or do the passengers on one going the other way get turfed off so that it can go over a crossover and back down onto the failure?

I was really hoping that the answer would be that a Unimog or something similar with a tram coupling would streak through the traffic, back down on the failure and tow it to the depot, minimising the delays to all the other trams in the queue.

 

[Mothball]

Despite all there flaws, the M5000s are pretty good at getting themselves home rather than needing recovering.
When they do there's numerous factors but if the vehicle is totally dead then its usually along the same lines.
As the brakes are electrically controlled the dead M5000 will have them manually isolated and be "Top and tailed", with a good vehicle coupled to both ends of the failed one. The rear one provides extra pushing/braking and acts as a failsafe in the unlikely event a coupler should fail. The three vehicles will then make there way back to a depot, or a siding/terminus out of the way, at reduced speed.

While the SPV (Diesel loco) is capable of such a move, and reguarly did on the unelectrified workshop roads at Queens Road, its more practical using other M5000s. As a side note the SPV is now out of use and hadn't been out on the mainline for a couple of years anyway.

 

[AndrewE]

Despite all there flaws, the M5000s are pretty good at getting themselves home rather than needing recovering.
When they do there's numerous factors but if the vehicle is totally dead then its usually along the same lines.
As the brakes are electrically controlled the dead M5000 will have them manually isolated and be "Top and tailed", with a good vehicle coupled to both ends of the failed one. The rear one provides extra pushing/braking and acts as a failsafe in the unlikely event a coupler should fail. The three vehicles will then make there way back to a depot, or a siding/terminus out of the way, at reduced speed.

While the SPV (Diesel loco) is capable of such a move, and reguarly did on the unelectrified workshop roads at Queens Road, its more practical using other M5000s. As a side note the SPV is now out of use and hadn't been out on the mainline for a couple of years anyway.

That sounds even worse! Do you really then empty the following tram to push the failure, and terminate one going the other way to reverse back onto it to provide a working cab? To eventually set off to the depot at reduced speed (further delaying the ones behind.)
They need a Unimog which can couple up and charge and control the brakes.

 

[WatcherZero]

Far faster to use the one 6/12 minutes behind than wait half an hour, possibly an hour for a unimog.

 

[507 001]

That sounds even worse! Do you really then empty the following tram to push the failure, and terminate one going the other way to reverse back onto it to provide a working cab? To eventually set off to the depot at reduced speed (further delaying the ones behind.)
They need a Unimog which can couple up and charge and control the brakes.

As Mothball says above, M5000s are usually pretty good at limping home or to a siding out of the way. In 10 years of driving I’ve only ever had 4 failures, and all were able to get me back to the depot, albeit slowly. Only two of those failures required me to do any isolating of systems.

If we get to the point where one has to be too and tailed back, the service will already be so far up the swanny that it won’t really matter what you do.

We have a unimog, but it won’t be able to control the brakes of an M5000 purely because there’s not much to control. They have rheo/regen braking and a hydraulically released, spring applied parking brake. If one is in such a condition that it needs to be dragged the parking brake needs to be wound off and pinned anyway, so the mog will be no better than another M5000.

Also, the reason they’re top and tailed;

A single M5000 can drag quite a bit of weight, and can stop a fair bit of weight too. However with the one being dragged being a swinger, there would be nothing to stop it should the coupler fail. The tailing M5000 is provided to be the failsafe against such an instance.

 

[Mothball]

That sounds even worse! Do you really then empty the following tram to push the failure, and terminate one going the other way to reverse back onto it to provide a working cab? To eventually set off to the depot at reduced speed (further delaying the ones behind.)
They need a Unimog which can couple up and charge and control the brakes.

Not counting in that I'm not sure a Unimog could reliably tow a 40 ton tram up a number of the inclines on the system, it would still have to get from a depot to a point where it can transfer from road to rail and reverse back down.

If the trams fully isolated the brakes will be inoperable so will have to be isolated regardless of what's towing.
 

 

[507 001]

Not counting in that I'm not sure a Unimog could reliably tow a 40 ton tram up a number of the inclines on the system, it would still have to get from a depot to a point where it can transfer from road to rail and reverse back down.

If the trams fully isolated the brakes will be inoperable so will have to be isolated regardless of what's towing.
 

The new one is reportedly quite happy pulling a double unit around…

 

[Mothball]

Despite all there flaws, the M5000s are pretty good at getting themselves home rather than needing recovering.
When they do there's numerous factors but if the vehicle is totally dead then its usually along the same lines.
As the brakes are electrically controlled the dead M5000 will have them manually isolated and be "Top and tailed", with a good vehicle coupled to both ends of the failed one. The rear one provides extra pushing/braking and acts as a failsafe in the unlikely event a coupler should fail. The three vehicles will then make there way back to a depot, or a siding/terminus out of the way, at reduced speed.

While the SPV (Diesel loco) is capable of such a move, and reguarly did on the unelectrified workshop roads at Queens Road, its more practical using other M5000s. As a side note the SPV is now out of use and hadn't been out on the mainline for a couple of years anyway.

how do you mean a failsafe witb a tram being on both ends and what happens if it breaks down at a end station by the buffers and thankyou

and what is a unimog thankyou

 

[Mothball]

The new one is reportedly quite happy pulling a double unit around…

I'm yet to see it in all its glory. I'm told its shiny though

how do you mean a failsafe witb a tram being on both ends and what happens if it breaks down at a end station by the buffers

and what is a unimog thankyou

So as the broken tram will have no brakes, if the coupler fails it can roll away, having a tram on the back means that tram can stop it from rolling away.
A Unimog is basically a type of truck, that is set up to drive on roads and rails

 

[507 001]

how do you mean a failsafe witb a tram being on both ends and what happens if it breaks down at a end station by the buffers and thankyou

and what is a unimog thankyou

So if you have one pulling a dead one, they’re only mechanically coupled, so if the dead one were to break away there’s nothing to stop it. With another powered up M5000 on the back, if the coupling breaks there will always be something powered up that can brake the dead unit to a stand.

If you were to break down at a terminus usually it would be left there until it could be recovered (probably at the end of service). Some shunting would be needed to get the dead unit into a safe top and failed formation.

A unimog is essentially a truck made by Mercedes. Ours has railway wheels so it can be driven on the track.

 

[Mothball]

thankyou all it sounds like a lot of work ive never seen it happen and i have been using the metrolink fir a while but if it does not happen often then i doubt i will see it

 

[BJames]

Not Manchester, but there are some pictures of a failed NET tram in Nottingham being towed by another in this article: https://westbridgfordwire.com/video-how-does-nottinghams-tram-operator-recover-broken-down-trams/

Pictures and video show the detail of how Nottingham Express Transit and Alstom engineers move trams which have failed on the network.

Today Saturday 25 February almost the entire tram network in Nottingham was down because of a system-wide fault, a broken overhead cable and a failed tram in Old Market Square.

And a video here:

https://www.tiktok.com/video/7204190395129924869

 

[Mothball]

thats an interesting view i can see the diference with the notingham tram not havi g the couplings likw metrolink do but that makes sense as they dont run double trams

 

[LOL The Irony]

and what is a unimog thankyou

A series of heavy duty off road vehicles built by Mercedes and designed as a post-war tractor replacement that could also be driven on road, similar to the Series 1 Land Rover. They are quite popular as road rail vehicles thanks to their versatility (some models allow you to change the hand of drive from inside the cab).

 

[AndrewE]

and what is a unimog thankyou

a simple websearch selecting wikipedia would have helped you if you had looked for about 10 seconds... https://en.wikipedia.org/wiki/Unimog
shows that there are lots of variants, and I'm sure a big-engined one could be built, maybe ballasted if necessary and with a compressor and air reservoir and auxiliary electric power supply or whatever the trams need to power the brakes on the failed unit.
This would surely be better than taking the tram behind out of service and chopping one in the opposite direction just to tow the failure out of the way.

Not counting in that I'm not sure a Unimog could reliably tow a 40 ton tram up a number of the inclines on the system, it would still have to get from a depot to a point where it can transfer from road to rail and reverse back down. 

Articulated lorry tractors move 40 (44?) tonnes gross, so why not a rescue tractor? I thought rubber tyres on tarmac had better adhesion than steel wheels on steel rails.
And waiting for a rescue tractor doesn't address the inconvenience to passengers of abruptly taking out of service a tram that was going in the opposite direction.

So if you have one pulling a dead one, they’re only mechanically coupled, so if the dead one were to break away there’s nothing to stop it. With another powered up M5000 on the back, if the coupling breaks there will always be something powered up that can brake the dead unit to a stand.

Pardon me, but I thought that railway and tram couplings were designed not "to break away." Don't trams have continuous brakes? [edit: and if the couplings are so fragile, maybe they will have auxiliary safety chains like the old narrow-gauge railways did a couple of hundred years ago] And if the trams can run as doubles, can't my imagined Uniomg pretend to be the front tram so that the back one will automatically stop if they come apart?

Far faster to use the one 6/12 minutes behind than wait half an hour, possibly an hour for a unimog.

As my mum used to say, "Use your nous!" Of course you can't: a) it's not running because it is (or will eventually be) pushing the failure, and b) the next one after that has been standing waiting ages for one going the other way to be taken out of service, run to a reversing crossover and then run back against the traffic flow (how long does it get enough policemen out to control that?) to couple up in front of the failure. Then drag the failure out of the way (at severely reduced speed apparently) - by which time everyone will have given up, transferred to a bus or just walked to their destination.

 

[WatcherZero]

As my mum used to say, "Use your nous!" Of course you can't: a) it's not running because it is (or will eventually be) pushing the failure, and b) the next one after that has been standing waiting ages for one going the other way to be taken out of service, run to a reversing crossover and then run back against the traffic flow (how long does it get enough policemen out to control that?) to couple up in front of the failure. Then drag the failure out of the way (at severely reduced speed apparently) - by which time everyone will have given up, transferred to a bus or just walked to their destination.

Your not following, its far faster to use the one behind to top and tail than wait for a unimog from the depot (exception being if theres wires down but then none are moving till they are repaired), you can clear the blockage before a unimog would even arrive which means service recovers faster. As to running against the traffic flow it depends on the line but generally theres a crossover every three stops or so but even the on-street lines are mostly segregated such that theres only a few locations where it would be against traffic flow (the blue sections on this map) and a Unimog would be preferable.

Gleisplanweb.de

 

[Mothball]

Pardon me, but I thought that railway and tram couplings were designed not "to break away." Don't trams have continuous brakes? [edit: and if the couplings are so fragile, maybe they will have auxiliary safety chains like the old narrow-gauge railways did a couple of hundred years ago] And if the trams can run as doubles, can't my imagined Uniomg pretend to be the front tram so that the back one will automatically stop if they come apart?

Of course they're designed for it, but when you have 40 tonnes of unbraked vehicle, its a pretty good idea to have a failsafe in place.

auxiliary electric power supply or whatever the trams need to power the brakes on the failed unit.

The hydraulic braking is controlled through a large unit on the underside of each half that controls almost all of the low voltage systems. It can not be isolated and controlled as a standalone system. If it cant be electrically coupled then the hydraulic brakes have to be isolated. Even if you could control the hydraulics from a towing vehicle, it only kicks in at around 5mph and below, everything else Is regenerative, so you still have 40 tons pushing against the recovery vehicle.
If the tram has power but cant move itself there is a way to hold the breaks released from the cab and save the top and tail but that's A, rarer than a total failure and B, a whole other story.

Funnily enough these tram operators know what they are doing, and if there was a faster, safer method then that's the one they would use. Its a very rare occurance and the tried and tested system in place works.

 

[507 001]

Pardon me, but I thought that railway and tram couplings were designed not "to break away." Don't trams have continuous brakes? [edit: and if the couplings are so fragile, maybe they will have auxiliary safety chains like the old narrow-gauge railways did a couple of hundred years ago] And if the trams can run as doubles, can't my imagined Uniomg pretend to be the front tram so that the back one will automatically stop if they come apart?

As my mum used to say, "Use your nous!" Of course you can't: a) it's not running because it is (or will eventually be) pushing the failure, and b) the next one after that has been standing waiting ages for one going the other way to be taken out of service, run to a reversing crossover and then run back against the traffic flow (how long does it get enough policemen out to control that?) to couple up in front of the failure. Then drag the failure out of the way (at severely reduced speed apparently) - by which time everyone will have given up, transferred to a bus or just walked to their destination.

I think you’re missing the point. We operate many, many thousands of miles with double units every year. The couplings aren’t fragile, they’re standard railway Sharfenberg heads, but nothing is ever 100% reliable.
In normal operation yes they have continuous brakes in the form of the spring applied parking brake, but with a dead one you don’t have anything on that particular vehicle, and you have no continuity through the train wires as the electrical boxes will not be connected (to keep from transmitting the fault to the good sets).

So with no continuity, no spring applied and the coupler under a considerable amount more stress than it would normally be, you have to have something to mitigate against the very slight chance of them coming apart.

And again, with a dead vehicle it doesn’t matter what communication the unimog can achieve with the M5000, if it’s dead, it’s dead.

On your second point, as I’ve said this is used as a very last resort, and the service will be suspended by the time you’re anywhere near recovering a dead set. In the 15 years we’ve been operating M5000s, we’ve had to do this a handful of times, mostly after pantograph damage or some other catastrophic failure. 99 times out of 100 they will self recover at a reduced speed, very occasionally they’ll go into ‘degraded mode’ and a vanishingly small amount of times they’ll sit down and decide they’re going no further.

Articulated lorry tractors move 40 (44?) tonnes gross, so why not a rescue tractor? I thought rubber tyres on tarmac had better adhesion than steel wheels on steel rails.
And waiting for a rescue tractor doesn't address the inconvenience to passengers of abruptly taking out of service a tram that was going in the opposite direction.

As is often the case, it’s not the getting it going that’s a problem, it’s the getting it to stop…

 

[AndrewE]

Your not following, its far faster to use the one behind to top and tail than wait for a unimog from the depot (exception being if theres wires down but then none are moving till they are repaired), you can clear the blockage before a unimog would even arrive which means service recovers faster. As to running against the traffic flow it depends on the line but generally a crossover every three stops or so but even the on-street lines are mostly segregated.

apart from the passengers needs...
The one behind obviously can't top and tail by itself, so that is 2 trams out of traffic straight away, plus the delay from the setting up - and the slow right-line recovery to the depot. I can't believe that what is needed to take trams out of traffic in both directions would really be quicker. But maybe this is one of those instances when cost of service recovery is more than ensuring reliability for the customers.

I think you’re missing the point. We operate many, many thousands of miles with double units every year. The couplings aren’t fragile, they’re standard railway Sharfenberg heads, but nothing is ever 100% reliable.
In normal operation yes they have continuous brakes in the form of the spring applied parking brake, but with a dead one you don’t have anything on that particular vehicle, and you have no continuity through the train wires as the electrical boxes will not be connected (to keep from transmitting the fault to the good sets).

So with no continuity, no spring applied and the coupler under a considerable amount more stress than it would normally be, you have to have something to mitigate against the very slight chance of them coming apart.

on the railway a continuous brake is one that applies the brakes on both portions of the train in motion if it parts. A parking brake is a bit different.
I have never heard of a continuous hydraulic brake, but if it is just electrically powered and controlled then why not have a power supply from the assisting vehicle? Sounds like a specification or design failure to me.

The hydraulic braking is controlled through a large unit on the underside of each half that controls almost all of the low voltage systems.

then can an assisting vehicle (Tram or unimog) really not supply enough power to the failed vehicle so that the brakes will work?

I'm very glad to hear that it is hardly ever needed...

 

[507020]

While the SPV (Diesel loco) is capable of such a move, and reguarly did on the unelectrified workshop roads at Queens Road, its more practical using other M5000s. As a side note the SPV is now out of use and hadn't been out on the mainline for a couple of years anyway.

The Metrolink had a Spectrum Pursuit Vehicle? Was it driven facing backwards?

If we get to the point where one has to be too and tailed back, the service will already be so far up the swanny that it won’t really matter what you do.

We have a unimog, but it won’t be able to control the brakes of an M5000 purely because there’s not much to control. They have rheo/regen braking and a hydraulically released, spring applied parking brake. If one is in such a condition that it needs to be dragged the parking brake needs to be wound off and pinned anyway, so the mog will be no better than another M5000.

The parking brake being audible every time a tram stops or starts, so all Metrolink passengers will be aware of it, but other than that, do they purely use rheo/regen for deceleration with no friction or air braking? I have been on a tram which was in the unfortunate enough situation to hit someone, so I have experienced an emergency brake application (and the driver made an announcement that we would not be able to move again until he had reported having made an emergency brake application) and it is really very sharp, not at all like train brakes requiring miles to stop.

If you were to break down at a terminus usually it would be left there until it could be recovered (probably at the end of service). Some shunting would be needed to get the dead unit into a safe top and failed formation.

Notably many of the termini have 2 platforms, even if at the end of a single track and only 1 is used in normal service, so I am assuming that this is what this is for. If a tram failed north of Shaw, would it be more likely taken at reduced speed to the 2nd platform at Rochdale and left there, rather than screw up the service trying to get it all the way back down to the depot?

on the railway a continuous brake is one that applies the brakes on both portions of the train in motion if it parts. A parking brake is a bit different.
I have never heard of a continuous hydraulic brake, but if it is just electrically powered and controlled then why not have a power supply from the assisting vehicle? Sounds like a specification or design failure to me.

Clearly, since this is a discussion about light rail, different design philosophy applies. It appears that the M5000s do not require a continuous air brake of the Westinghouse type as heavy rail vehicles do. It's obvious why a failed vehicle can't be powered. The fact that an M5000 is able to both drag and stop a failed unit using only rheostatic and regenerative braking, on any of the steep gradients on the system, bearing in mind that the couplers are usually only used with both trams powering, is a considerable achievement. They sound very well specified to me.

 

[LOL The Irony]

The Metrolink had a Spectrum Pursuit Vehicle? Was it driven facing backwards?

Do they have to show their metrolink identification and does it come out of a t68?

 

[randyrippley]

I'm sure I've seen a Unimog (on tyres) towing a tram in Blackpool
but maybe it's safer there: no real hills

 

[Mothball]

these are all very intresting comments and some good ideas thankyou