Cracks found in Comeng bogies

 
  alstom_888m Chief Commissioner

Location:
http://www.theage.com.au/victoria/cracks-found-in-metro-train-bogies-20131223-2zumq.html
Potentially dangerous cracks have been found on 18 Metro rail carriages, forcing the state government to spend millions on replacement parts for Melbourne's ageing Comeng fleet.

Metro has begun repair work on 18 carriages where cracks have been identified, although it believes any patch-up job is likely to be temporary. The cracks are also likely to affect more of Melbourne's train fleet, Metro said in an internal document, potentially cutting short the damaged carriages' service life.

The cracks are confined to the bogies of some of Metro's Comeng trains, which began to come into service in 1981. The trains are due to be taken out of service in 2024.

Bogies are part of the load-bearing structure beneath a train carriage, so any severe cracking is a threat to passenger safety and could potentially derail a train.

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In January, V/Line pulled 22 of its older carriages out of service for repairs due to cracked bogies. It took until June for the first of them to be returned to service.

A leading rail engineer said passenger safety would depend on how closely Metro monitored the cracking. ''It's very unlikely to end up in anything catastrophic,'' he said. ''It's always possible, but it really goes to the strength of Metro's surveillance, how closely they're inspecting them.''

The cracking in Metro's trains was identified late last year, according to an internal report written in March. It warns that although the damage is confined to just 18 trains, it is likely to spread.

''Given the nature of the failure, the cracks can be expected to spread across the population of LHB bogies,'' the document states. ''A weld repair procedure has been developed. Welded repairs are at best likely to be a stop-gap measure as the area around the weld will be affected by heat, creating conditions for further failures. Whether we can get through to the proposed end of life of these trains [2024] is problematical.''

Any carriage with a crack more than 80 millimetres long will be taken out of service for repair, and any bogie with a crack greater than 120 millimetres is recommended to be scrapped, the document says.

The problem is being caused in part by the condition of the tracks on the metropolitan rail network.

Transport Minister Terry Mulder said the cracking was confined to 30 six-carriage Comeng trains with disc brakes and fabricated bogies. Four bogies have already been replaced, he said.

''Public Transport Victoria is finalising discussions with Alstom to supply 100 replacement bogies along with options for up to 75 more at a total cost of more than $5 million,'' he said. ''This will extend the life of these Comeng trains if necessary, although the Coalition government has already ordered or placed in service 15 new six-carriage suburban trains and will continue to consider the renewal of Melbourne's train fleet.''
"The Age"


Given that we can't even seem to phase out the remaining Hitachi, we are going to have a major train shortfall in the medium-term. Note the article states the issues are with trains with disc brakes; these are the second series of Comeng.

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  fabricator Chief Commissioner

Location: Gawler
So in other words, M 561 - 680 and T 1131 - 1190.

I'm wondering if in the longer term, Adelaide 3000 class railcars could also have this problem as they have fabricated bogies as well, and seemingly of the same design. I know there was talk at one stage with SA ordering a full replacement set of cast bogies as part of the electrification/standard gauge conversion of the fleet.
  don_dunstan Minister for Railways

Location: Adelaide proud
So in other words, M 561 - 680 and T 1131 - 1190.

I'm wondering if in the longer term, Adelaide 3000 class railcars could also have this problem as they have fabricated bogies as well, and seemingly of the same design. I know there was talk at one stage with SA ordering a full replacement set of cast bogies as part of the electrification/standard gauge conversion of the fleet.
fabricator
In Adelaide they suffered from the same issues as we did in Victoria; parts of the network very sub-standard.  Hopefully that issue has been substantially resolved with the re-construction of the whole system.  They've been doing the same thing here in Victoria but it's a much larger network and it's been a really slow process.

Incidentally if the disc-brake Comengs are cracking then I wonder how the Alstom Xtrapolis will fare in the longer term?  Their construction seems (to a non-engineer like me) a lot less robust, particularly with the lack of an air-bag suspension.
  sparkdriver Assistant Commissioner

Location: Melbourne
The most positive thing written in that article is that the Comeng's are planned to be kept in service until 2024, which means they will be over 40 years old by that time. They are clapped out now and they're still going to be around for another decade.....Rolling Eyes
  ALMOST610 Station Master

The most positive thing written in that article is that the Comeng's are planned to be kept in service until 2024, which means they will be over 40 years old by that time. They are clapped out now and they're still going to be around for another decade.....Rolling Eyes
sparkdriver
The fact they have not even started planning for replacement trains to get rid of them means they should be around for a while, perhaps with another refurb in the middle.
  Heihachi_73 Chief Commissioner

Location: Terminating at Ringwood
Wouldn't it be cheaper to simply replace irreparable bogies with the older tread brake bogies, or isn't it possible to do this? Maybe a few Hitachi bogies should have been put aside. Laughing
  712M Chief Commissioner

Wouldn't it be cheaper to simply replace irreparable bogies with the older tread brake bogies, or isn't it possible to do this? Maybe a few Hitachi bogies should have been put aside. Laughing
"Heihachi_73"

Surely these would be long out of production by now
  The Vinelander Minister for Railways

Location: Ballan, Victoria on the Ballarat RFR Line
The most positive thing written in that article is that the Comeng's are planned to be kept in service until 2024, which means they will be over 40 years old by that time. They are clapped out now and they're still going to be around for another decade.....Rolling Eyes
sparkdriver
Clapped out Question

Nar....not even close. What was clapped out were the Taits that were still in operational service in 1983, 50+ years after they were built.

Mike.
  Braddo Deputy Commissioner

Location: Narre Warren
The Comengs are well and truly clapped out from a mechanical point of view, the most annoying problem with them is that the compressors are running almost constantly. I wish they'd do something about it as having only 2 out of 6 cars suitable for use is not good enough.
  YM-Mundrabilla Minister for Railways

Location: Mundrabilla but I'd rather be in Narvik
Only in the space of 10 days in late November/early December I noted three Comengs running with only three pantographs raised. Are these trains evidence of a maintenance backlog or other ongoing reliability issues.

Comeng airconditioning is little, if any, better than it ever was and one wonders if this is another factor contributing to Metro's cancellations under the guise of rails that might buckle.
  frezno Junior Train Controller

The Comengs are well and truly clapped out from a mechanical point of view, the most annoying problem with them is that the compressors are running almost constantly. I wish they'd do something about it as having only 2 out of 6 cars suitable for use is not good enough.
Braddo
Dude, if you find the compressors so bad that you simply cannot sit in a carriage with one running, maybe you should get yourself a chauffeur and limousine? The comeng's really aren't that bad. They are old and get faults, yes, so will anything with mechanical components. But they make up a large part of the fleet and if they were gone tomorrow there'd be anarchy due to the lack of services able to run. They're far comfier than an XTrap. Deal with it or get used to driving.
  712M Chief Commissioner

Dude, if you find the compressors so bad that you simply cannot sit in a carriage with one running, maybe you should get yourself a chauffeur and limousine? The comeng's really aren't that bad. They are old and get faults, yes, so will anything with mechanical components. But they make up a large part of the fleet and if they were gone tomorrow there'd be anarchy due to the lack of services able to run. They're far comfier than an XTrap. Deal with it or get used to driving.
"frezno"

Or sit in a T carriage...?
  alstom_888m Chief Commissioner

Location:
It's the "whine" of the alternator on the disc sets that annoys me; if one rocks up, I prefer the T car. My line these days seems to be 90% X'Trap however.

Notice most Comeng complaints are directed at the newer disc sets?
  Braddo Deputy Commissioner

Location: Narre Warren
Dude, if you find the compressors so bad that you simply cannot sit in a carriage with one running, maybe you should get yourself a chauffeur and limousine? The comeng's really aren't that bad. They are old and get faults, yes, so will anything with mechanical components. But they make up a large part of the fleet and if they were gone tomorrow there'd be anarchy due to the lack of services able to run. They're far comfier than an XTrap. Deal with it or get used to driving.
frezno
Why should I have to deal with it? Something as important as a braking system should be properly maintained.
  frezno Junior Train Controller

712M, Braddo stated that the world was caving in to a firey apocalypse because he only had the option of 2 out of 6 cars (I'm therefore assuming he absolutely positively won't sit in anything other than a T car on a Comeng)

Braddo, you're probably lucky more of the compressors don't actually run continuously, considering that's what they're designed to do. What is it that makes you think they are not properly maintained because they are noisy? A compressor compresses air. That's a noisy task. Have you ever used a little compressor for inflating tyres? Yep, they're noisy too.

Considering the job of the compressor would be to supply air to the train, it would supply ALL of the air, not just to the braking systems. That would be everything from holding the doors closed to keeping the pantographs raised to enabling the whistle to operate. Seems like a pretty darn important piece of machinery to me.

I stick with my comment above. If you're too precious to sit in a carriage with a working compressor, wait for the next train, and maybe the next, and maybe the next.. Or better yet get a taxi and have something to really complain about.

I'd rather sit in a carriage with 50 compressors running full tilt than one child.
  don_dunstan Minister for Railways

Location: Adelaide proud
It's the "whine" of the alternator on the disc sets that annoys me; if one rocks up, I prefer the T car. My line these days seems to be 90% X'Trap however.

Notice most Comeng complaints are directed at the newer disc sets?
alstom_888m
Apparently the design of those bogies - specifically for discs - is the core of the problem.
  Braddo Deputy Commissioner

Location: Narre Warren
An air compressor is NOT designed to run continously. It runs when the air in the tank has gone below a certain level. There is obviously a leak or some other sort of issue on the cars where the compressor is running almost constantly. Have you not noticed that some motors can run for many stations without the compressor firing up, yet on others it is firing up after the train stops at every single station?

My issue is not with the noise but with the annoying vibration it causes. Of course, it doesn't even come close to annoying me as much as an arrogant smartass.
  FullSeries Assistant Commissioner

Location: Sydney, NSW
An air compressor is NOT designed to run continously. It runs when the air in the tank has gone below a certain level. There is obviously a leak or some other sort of issue on the cars where the compressor is running almost constantly. Have you not noticed that some motors can run for many stations without the compressor firing up, yet on others it is firing up after the train stops at every single station?

My issue is not with the noise but with the annoying vibration it causes. Of course, it doesn't even come close to annoying me as much as an arrogant smartass.
Braddo
This just shows a lack of understanding about the mechanics of air systems on trains. Compressors are controlled by a compressor governor. Brake systems use the majority of the air, with doors and control systems also. These trains are 30 years old. Parts will get leaks, even replacement parts will leak. I agree that the rubber mounts are not perfect, but I just don't see the big issue here? Trains require 3 things, High Tension, Low Tension and Air. Whatever it takes to produce and keep these things working should be seen as a good thing - not an annoyance.
  M636C Minister for Railways

There would seem to be an element of "You reap what you sow" here...

The second batch of Comeng cars were a substitute for the rebuilding of Harris cars in the "Grey Ghost" program, when it was realised that the cost of the rebuilding was too high.

To digress for a moment. Some years ago I was taking photos around Grand Junction Road at the north end of Islington Freight Centre in Adelaide. As in many places where level crossings have been replaced by overpasses, the fences had been (unofficially) removed to allow pedestrians to cross the old level crossing site. Anyway it allowed me to cross the line for photos without a long walk. When crossing the line I found a small rectangular metal plate, and of course picked it up. i don't have it handy (I'm interstate for the Holiday Season right now).

It was a bogie plate from a 3000 class, and read something like (from memory)

"State Transit Authority of South Australia"

"Bogie Number....."

"Built by the Public Transport Commission of Victoria at their Bendigo Workshops under licence to Linke Hoffmann Busch (date)"


So I assume that the Victorian bogies were built there too, presumably as a trade off for the work lost in not performing the Harris upgrades, and that lowered the contract price compared to buying new cars with Bradken cast bogies, while providing better braking for the cars destined for the hilly Eastern lines.

However, The Victorian Government can't complain about poor workmanship to anybody else in this case.

I assume that the new bogies they are talking to Alstom about are new frames of the same design, to be built under the same licence.

I understand the motor alternator sets used on disc brake Comeng cars was a unit already in stock for the Harris upgrade program.

M636C
  frezno Junior Train Controller

An air compressor is NOT designed to run continously. It runs when the air in the tank has gone below a certain level. There is obviously a leak or some other sort of issue on the cars where the compressor is running almost constantly. Have you not noticed that some motors can run for many stations without the compressor firing up, yet on others it is firing up after the train stops at every single station?

My issue is not with the noise but with the annoying vibration it causes. Of course, it doesn't even come close to annoying me as much as an arrogant smartass.
Braddo

*sigh*

Ok, douchebag. This is why you're wrong - An air compressor IS designed to run continuously.

I'm not debating whether there is a fault with it, a leak in the supply reservoir or hose causing it to run continuously, simply that it is designed to run continuously.

They build air compressors with the materials and longevity to enable them to run continuously in the event of a fault. For example, so that we don't have trains becoming disabled in peak hour in the middle of nowhere because a governor is not set correctly and rather than the compressor running continuously (like it would now), it just shuts off and doesn't start back up again.

Therefore, if it is running continuously there is no urgency with which to deal with it because it is designed to do this. This is subsequently why you will find, if an air compressor is running continuously on a train, it will come up as the lowest fault category to be fixed at a time that is convenient for the company. In 7 day or 3 months.

You are the arrogant smartass, trying to talk crap to someone whose job this is for a living. *facepalm*
  YM-Mundrabilla Minister for Railways

Location: Mundrabilla but I'd rather be in Narvik
Perhaps the keywords here are 'intended' versus 'designed'. On a six car train with four motor cars there will be four compressors which may well be designed to run continuously. However, it is only intended that whatever number run whenever needed to maintain the required main reservoir pressure.

Motor alternators, which do run continuously, can be equally or even more annoying when their bearings are shot.

Another question concerning Comengs is why, usually when accelerating, does the aircon and fans go off together with half the lights?
  shrekman Junior Train Controller

Location: E.R.D.
Its a power supply issue YM. Generally an MA will drop out for a split second because its supply voltage has dropped as the line breakers start putting 1500V through to the traction motors. There are a few common spots for it, Westona is one that comes to mind. Most times only one MA that is probably the most worn on the train will drop out allowing enough voltage for the others to keep operating, and because each MA in a three car set powers half the lights and half the aircon, thats the result you experience.

(MA = Motor Alternator)
  YM-Mundrabilla Minister for Railways

Location: Mundrabilla but I'd rather be in Narvik
Its a power supply issue YM. Generally an MA will drop out for a split second because its supply voltage has dropped as the line breakers start putting 1500V through to the traction motors. There are a few common spots for it, Westona is one that comes to mind. Most times only one MA that is probably the most worn on the train will drop out allowing enough voltage for the others to keep operating, and because each MA in a three car set powers half the lights and half the aircon, thats the result you experience.

(MA = Motor Alternator)
shrekman

Many thanks Shrekman for your comprehensive reply.
The acronym explanation ('MA = Motor Alternator') is a concept that many on Railpage would do well to emulate as so many threads have become almost meaningless due to acronyms and jargon.
  FullSeries Assistant Commissioner

Location: Sydney, NSW
Another one that was bad was Upper FTG to Belgrave. When sitting on the platform you could hear the MA go from 50Hz down to 35/40Hz.
  YM-Mundrabilla Minister for Railways

Location: Mundrabilla but I'd rather be in Narvik
Given that the prime thrust of this thread is compressors that run continuously it seems to me that there are a few main reasons for this to occur (at least with the Taits one was under no illusion as to whether the compressor was running or not!):


  1. The governor on the pump in question is shot in which case it pumps regardless of whether air is needed or not. Whilst this is, perhaps, unlikely, I assume that there is a safety valve in the system somewhere which would blow more or less continuously.

  2. The combined compressors on the train are unable to maintain the required main reservoir pressure and the train runs with a level of reduced repetitive braking capacity.

  3. I assume that a driver can cut out a level of defective compressors enroute if necessary?



A question for our fearless drivers perhaps?

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