WA Radio Scanner Users' Group

TheWest wrote:Meanwhile two rail cars, believed to be involved in repair works near Warwick Station, have collided this morning. No injuries have been reported.

http://au.news.yahoo.com/thewest/a/-/wa ... -services/

Zebedee wrote:

doggie015 wrote:Now the fremantle and armadale/thornlie lines are delayed due to a "Technical issue"... This has not been a good 24 hours for TransPerth...

Apparently the issue with the Fremantle line this morning was a railcar that decided to fail just in or near Fremantle station. They had to haul it out of the way before they could get things going again.

Yikes! Better in/near station than inbetween stations I guess...

Also: i heard on the radio this morning that apparently the incident still in effect today was caused by the overhead pantograph and that the pantograph has apparantly caught the lines 2 times before, but not nearly as bad as this! (It wasn't confirmed that the pantograph was the cause in the last 2 cases, Troy said that having the investigation turn up "Inconclusive" would not be good enough this time)

doggie015 wrote: Also: i heard on the radio this morning that apparently the incident still in effect today was caused by the overhead pantograph and that the pantograph has apparantly caught the lines 2 times before, but not nearly as bad as this

I could understand how an old-fashioned tram power pickup could catch but how does the pantograph catch on the line? It slides along it underneath?

My thinking (guessing) is that a line was loose, no longer connected to the pole boom and the line managed to slip under the pantograph. Looking at some designs similar to this http://en.wikipedia.org/wiki/File:Stras ... ograph.jpg I don't see how the cable can get back out easily once trapped underneath, and once it hits the next boom (which would be pretty quickly at 100k's) it just starts ripping them out.

Again just a guess.

yorky wrote:My thinking (guessing) is that a line was loose, no longer connected to the pole boom and the line managed to slip under the pantograph. Looking at some designs similar to this http://en.wikipedia.org/wiki/File:Stras ... ograph.jpg I don't see how the cable can get back out easily once trapped underneath, and once it hits the next boom (which would be pretty quickly at 100k's) it just starts ripping them out.

Again just a guess.

One thing I find hard to believe is that it took the train so long to stop that it damaged 1.5k of supporting poles with it! Surely the emergency brakes would have bought it to a stop sooner (Assuming that they were even applied!)

We can really only speculate. But remember it was a fully loaded peak hour service, 4 car. Not something that stops quickly. Running at 100-110km/h the reaction time of the driver would have several booms destroyed before he even thinks about applying the brake.

Its also possible the first few booms that were getting bent were not noticeable to the driver until things started acting strange/banging. If the power loss was immediate that wouldn't (although I don't know procedures so again just guessing) make the driver think to apply full service brake right away since he is loaded (no point making passengers fall over/get hurt for little reason). He might at first think its just a power cut and in that case it would actually be an advantage not to touch the brake and coast into the station.

yorky wrote:We can really only speculate. But remember it was a fully loaded peak hour service, 4 car. Not something that stops quickly. Running at 100-110km/h the reaction time of the driver would have several booms destroyed before he even thinks about applying the brake.

Its also possible the first few booms that were getting bent were not noticeable to the driver until things started acting strange/banging. If the power loss was immediate that wouldn't (although I don't know procedures so again just guessing) make the driver think to apply full service brake right away since he is loaded (no point making passengers fall over/get hurt for little reason). He might at first think its just a power cut and in that case it would actually be an advantage not to touch the brake and coast into the station.

If the power failed the train would lose air pressure and as such (Assuming there is any logic in the brake design...) the full service brakes would be automatically applied due to the fail-safe design of air pressure dependant braking systems... It could have been a case of the front pantograph dislodging the wire while the rear one catches it and takes the poles with it... The driver was making announcements over the PA after the train had stopped so obviously there was still power being supplied to the train

doggie015 wrote:The driver was making announcements over the PA after the train had stopped so obviously there was still power being supplied to the train

Not necessarily. I've been in a train which has temporarily lost power. The train stops, the lights and aircon go off but the train PA still works. I'd imagine they'd have backup batteries just for this sort of thing.

From reading one of the articles the train carries a backup generator (I don't know if this is true, it could be backup batteries instead?) I'd say this powers critical systems like the PA/radio etc, the article also mentioned fans still running for a short period of time. I know when you run through an unpowered section of track the air con compressors disengage during that time.

Some small sections of track are unpowered, and they allow the train to pass through without air brakes being applied and with internal lighting still operating so I'm going to guess there is some sort of on board battery bank or something.

yorky wrote:From reading one of the articles the train carries a backup generator (I don't know if this is true, it could be backup batteries instead?) I'd say this powers critical systems like the PA/radio etc, the article also mentioned fans still running for a short period of time. I know when you run through an unpowered section of track the air con compressors disengage during that time.

Some small sections of track are unpowered, and they allow the train to pass through without air brakes being applied and with internal lighting still operating so I'm going to guess there is some sort of on board battery bank or something.

Probably... I've noticed the fans disengaging on the armadale line just before the train gets to claisebrook station (Inbound) or just after it leaves claisebrook station (Outbound)... Always happens at the same point in the line... I think that might be an unpowered section where the backup system kicks in. The fans still operating for a short time would be due to the residual power in the line after it was cut keeping the systems active.

A backup generator would be impractical because you have to have space for the generator, fuel and an engine to power the thing! Batteries take up less room and need less time to pick up the slack. If you're going to be having a generator you may as well do away with overhead wires and run everything on DMU's!


Actually that may not be such a crazy idea... certainly removes the risk of this happening again...

But think of all the exhaust fumes ruining the air, when they can run on nice clean electricity! No no, never mind where the electricity comes from!

Anyway, the air system would be already pressurised and I'd guess usable to apply brakes perfectly fine with no power, they just wouldn't be able to be disengaged again if it ran out of air until power is restored?

From my hazy memory of being in the cab of an A set, the emergency brake was a separate lever as well so would take longer to reach for it, where as the driver usually has his/her mitts on the combined throttle brake most of the time.

yorky wrote:...Anyway, the air system would be already pressurised and I'd guess usable to apply brakes perfectly fine with no power, they just wouldn't be able to be disengaged again if it ran out of air until power is restored?...

Well, that's how it's supposed to work after what happened to cause the Gare de Jyon rail accident ( http://en.wikipedia.org/wiki/Gare_de_Lyon_rail_accident )...

Damage is worse than first thought... they now hope to have it repaired on saturday

This is not a good week for TransPerth... another train has failed! This time at Mosman Park (to perth)

UPDATE: After the tests today were a success they are reopening the section of track this evening! =D>

Buses being organized for Mandurah line due to technical issue