July 07, 2022, 06:11:07 PM

Tram Discussion

Started by Barry Drive, April 21, 2019, 02:44:09 PM

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Barry Drive

This topic relates to the Trams/Vehicles, not the system.

To begin with: Canberra Metro claim their trams have WiFi on board. The one I was on today (006) certainly didn't. The air conditioning also wasn't working, but a technician got on board outside the depot and managed to get it working by about Nullarbor Ave.

triumph

The LRVs now have module identification underlined, with fleet number below, inside each module.

Module identifications are C1 - S1 - R - S2 - C2. This is slightly different from identification used by CAF (Mc-S-T-S-Mc).

Riding recently on several, orientation varied vehicle to vehicle, with LRV004 noted being reversed between 24th and 26th. This is very likely due to the Depot junction layout (eg an LRV commencing the day at Gungahlin and finishing the day at Alinga St would end up reversed when back in the Depot). Frequent random reversals would be a good thing as wear would be evened out (especially considering the dominant effect on wear by the one really sharp curve, Flemington/Federal Highway).

Busnerd

Quote from: triumph on April 28, 2019, 04:09:33 PMThe LRVs now have module identification underlined, with fleet number below, inside each module.

Module identifications are C1 - S1 - R - S2 - C2. This is slightly different from identification used by CAF (Mc-S-T-S-Mc).
Those were all installed prior to revenue service commencement, so not sure it's really a matter of them 'now' having it, as far as the public is concerned they always did.

triumph

Quote from: Busnerd on April 28, 2019, 10:12:39 PMThose were all installed prior to revenue service commencement, so not sure it's really a matter of them 'now' having it, as far as the public is concerned they always did.

Ok Ok I wasn't wearing my pedantry hat.

A while ago I attended a technical interest group's inspection. At that time someone in the group asked about module identification and (though the fleet already had numbers) this appeared to be an entirely new thought to our host. Thus the word 'now' popped into my mind without deep consideration.

The point of course, is that modules are identified and the identification system used is now on the Forum record.

triumph

Some time ago I remarked on the variable 'thrumming' noise coming from underneath various light rail vehicles as they travel along the track. Was this rail roughness or problems with wheels?

Have now come to conclusion that the wheels are the source and that the principle cause is various imperfections ('flat' spots) distributed both circumferentially and transversely on wheels. The random transverse distribution would tend to explain why the 'thrum' is partially inconsistent.

If, in fact, the wheels have developed minor imperfections, then the cause is most likely minor skids/slips during severe braking related to acceptance testing and/or performance validation, and to extensive driver training. The only solution, if imperfections as described are
present, is the wheel lathe.

Busnerd

Also perhaps running over the bark and rocks etc. in the track grooves could cause temporary 'flat spot' style noises.

triumph

Quote from: Busnerd on July 18, 2019, 03:25:38 PMAlso perhaps running over the bark and rocks etc. in the track grooves could cause temporary 'flat spot' style noises.

Agree any debris solid enough would result in audible noise and, if substantial, would be firmly felt too (note the clunks at pointwork).

The 'thrum' is particularly noticeable in the centre (R) module of some of the LRVs. Whilst of variable presence, when it is present, the frequency is quite uniform and varying with the speed variation of the LRV. It is mostly more obvious under acceleration/braking too. I am now convinced this points to wheel 'flats'. It remains possible that rail surface imperfections after grinding, and/or suspension/bearing vibrations might also contribute or aggravate the 'thrum', but I think wheel 'flats' is the priniciple source.

What did puzzle me for awhile, was the inconsistency of occurrence. It then occurred to me that track geometry and dynamic effects could move  the wheel - rail contact point transversely across the wheel. Thus if the 'flat' spot(s), as might be expected, did not extend across the full width of the wheel, then it is quite plausible that the 'flat' spot(s) would not always be contacting the rail.

Whilst the maintenance base might have a wheel lathe. With only 14 LRV I rather think not, with wheel sets being sent away for reprofiling.

Barry Drive

Tram 008 resumed service this week after its collision at Swinden St last month

Which is convenient timing.

triumph

Quote from: triumph on July 19, 2019, 12:06:11 AMWhilst the maintenance base might have a wheel lathe. With only 14 LRV I rather think not, with wheel sets being sent away for reprofiling.

I thought wrong. The maintenance base has a wheel lathe built into one of the 4 tracks within the maintenance building.

triumph

The Canberra Times today at page 12 (print version) reports on a thorough examination of LRV11 for cracking and found none. This followed the standing down of the Sydney fleet operating the Central to Dulwich Hill route after the discovery of cracking.
The item says that LRV11 is at the time of inspection, the most travelled of the fleet at 192,000km. It also remarks that (being of a slightly newer manufacture) that there are structural differences between the two CAF fleets (even though both are the same basic model).
Interestingly, in Sydney's fleet, cracking was found in the 'bump stop'. This implies to me rougher track with consequent stresses on their LRVs which do not apply to Canberra. Most of the Central- Dulwich Hill route uses former heavy rail track disused when freight trains ceased operating. As such with sleeper and ballast it is quite different to the arrangement in Canberra where rails are fixed in a concrete slot with a commercial fixing fill for an inherently smoother life. I recollect riding to Dulwich Hill a while back and wondering at the time what was to be done about track ballast maintenance, as the ride was quite rough here and there.
Another interesting detail I came across may provide a reason for the newer fleet used between Circular Quay and Kingsford/Randwick not being available to use to Dulwich Hill. The CAF Dulwich Hill route requires the LRV wheels to suit heavy rail profile, whereas the newer fleet has a profile to suit the newly laid street running track with normal grooved rail. The differences are subtle with no change in the basic gauge. And yes, the newer fleet can move along the Dulwich Hill route, under particular conditions, when needing to go to the heavy maintenance depot, but not for ordinary everyday running.

ajw373

Quote from: triumph on December 02, 2021, 10:17:56 PMThe Canberra Times today at page 12 (print version) reports on a thorough examination of LRV11 for cracking and found none. This followed the standing down of the Sydney fleet operating the Central to Dulwich Hill route after the discovery of cracking.
The item says that LRV11 is at the time of inspection, the most travelled of the fleet at 192,000km. It also remarks that (being of a slightly newer manufacture) that there are structural differences between the two CAF fleets (even though both are the same basic model).
Interestingly, in Sydney's fleet, cracking was found in the 'bump stop'. This implies to me rougher track with consequent stresses on their LRVs which do not apply to Canberra. Most of the Central- Dulwich Hill route uses former heavy rail track disused when freight trains ceased operating. As such with sleeper and ballast it is quite different to the arrangement in Canberra where rails are fixed in a concrete slot with a commercial fixing fill for an inherently smoother life. I recollect riding to Dulwich Hill a while back and wondering at the time what was to be done about track ballast maintenance, as the ride was quite rough here and there.
Another interesting detail I came across may provide a reason for the newer fleet used between Circular Quay and Kingsford/Randwick not being available to use to Dulwich Hill. The CAF Dulwich Hill route requires the LRV wheels to suit heavy rail profile, whereas the newer fleet has a profile to suit the newly laid street running track with normal grooved rail. The differences are subtle with no change in the basic gauge. And yes, the newer fleet can move along the Dulwich Hill route, under particular conditions, when needing to go to the heavy maintenance depot, but not for ordinary everyday running.

Biggest issue running the Alstom trams on the inner west line are floor height difference, in particular the Alstom is slightly lower which means when doors open they can hit the platform. Hence why they can operate out of service on the line.

Profile is also an issue but easily solved in the wheel lathe.

triumph

Quote from: ajw373 on December 08, 2021, 12:36:17 PMBiggest issue running the Alstom trams on the inner west line are floor height difference, in particular the Alstom is slightly lower which means when doors open they can hit the platform. Hence why they can operate out of service on the line.

Profile is also an issue but easily solved in the wheel lathe.

Yes, now you mention it, I think I did read something on floor heights and platforms. But not how much the difference was and hence how difficult that might be to work around.

The wheel issue however is not simply resolvable with a lathe. The Sydney Tramway Museum found that the Variotram could not run reliably on their tram style track until the wheels received lathe attention. The problem is the back to back gauge and interaction with heavy rail check rails. The Museum could have material removed and wheels re-profiled by using a lathe but material can hardly be added by a lathe as apparently would be needed for the Alstom trams.

ajw373

Interestingly they are now testing the Alstom trams in the inner west line. Maybe the floor height issue was a furphy or they plan to make some mods to allow them to work.

The wheel issue they are still not so sure about. Apparently when running to the heavy maintenance depot the Alstom trams run at a slower speed. A speed that would not be viable in operation, so they are going to push the limits to see how fast they can safely go.

narc855

But if you transfer some Alstom trams to L1, L2 and L3 will result in the shortage of trams.

However, I still think that it's more important to have trams running on L1. The layout of inner west line (L1) is mainly not on the side of the road which makes it hard to arrange replacment buses (check 2L1, 3L1, 4L1 on the anytrip). The layout of Randwick and Kingsford lines (L2 &L3), however, is mainly along the majors roads such that replacement buses can run the same line as LR.

Toyota Camry

Quote from: narc855 on December 10, 2021, 12:42:06 PMBut if you transfer some Alstom trams to L1, L2 and L3 will result in the shortage of trams.
Recently prior to the latest surge in case numbers in NSW, I undertook a weekend trip to Sydney; during this trip it was observed at Round Key that these lines operate 2 trams coupled together; however they are not full. L2 line can be downgraded to operating with 1 tram per service; this will provide fleet for the L1 line.

narc855

Quote from: Toyota Camry on December 11, 2021, 08:22:33 AMa weekend trip
So this is the problem. They are actually full at weekdays.