POLL: 12 minute cycles for Merivale Bridge lines

[somebody]

From this thread: http://railbotforum.org/mbs/index.php?topic=7269.0

5tph Varsity Lakes, express Beenleigh to Yeerongpilly stopping at Coopers Plains and Loganlea
5tph Beenleigh, express Park Rd to Yeerongpilly
5tph All to Manly
5tph Cleveland express Manly to Park Rd stopping at Morningside

Appropriate infrastructure on the Cleveland line would involve Thorneside-Wellington Point, some duplication beyond Wellington Point and possibly Manly-Lota duplication.

[#Metro]

I think there should be a policy that NO NEW LINES are to be built as single track.

[somebody]

That's my thinking also.  However, it seems that Cityrail have gone against that sort of thinking with fully duplicating the Cronulla branch which used to work that way, and you don't see them implementing something like that on the Richmond line.

[#Metro]

What should be looked at when single lines are built is rather than having a single passing loop around a station, the loop should be a lane that enables some minor flexibility before other trains are held up. Doomben line should have duplication to first station so passes can occur off the main, should the departing train be late.

Silly question but I have always wondered why trains couldn't have have a boarding track at stations, much like busways have two lanes at busway stations - a boarding lane and a passing lane.

[ozbob]

What should be looked at when single lines are built is rather than having a single passing loop around a station, the loop should be a lane that enables some minor flexibility before other trains are held up. Doomben line should have duplication to first station so passes can occur off the main, should the departing train be late.

Silly question but I have always wondered why trains couldn't have have a boarding track at stations, much like busways have two lanes at busway stations - a boarding lane and a passing lane.

This has been proposed before today by the RTBU and others, and looks like it will be done on the Trouts Road Corridor railway if implemented.

[mufreight]

What should be looked at when single lines are built is rather than having a single passing loop around a station, the loop should be a lane that enables some minor flexibility before other trains are held up. Doomben line should have duplication to first station so passes can occur off the main, should the departing train be late.

Silly question but I have always wondered why trains couldn't have have a boarding track at stations, much like busways have two lanes at busway stations - a boarding lane and a passing lane.

COST

[#Metro]

COST

It would be significantly cheaper than full duplication and much easier to schedule services in when the timetables need changing / more services added.
This allows for higher frequency and more passengers; better use of infrastructure.

[somebody]

Bifurcation.

I think it only makes sense when a small proportion of stations have a large proportion of the loadings.  Even then, once you add in run off areas for approaching the station at a reasonable speed, the cost adds up.  Compared to just adding a full extra path, I'm not sure how great an idea it actually is.

[HappyTrainGuy]

I fail to see how. Not to mention it stuffs up any future plans for all stoppers and express trains. Then comes the longer dwell times as you wait for the train behind to clear your signals and then waiting for the signals to clear from the train that just passed. It works for busways, not for trains. Put red lights on the busway to see how effective it really is.

[#Metro]

I fail to see how. Not to mention it stuffs up any future plans for all stoppers and express trains. Then comes the longer dwell times as you wait for the train behind to clear your signals and then waiting for the signals to clear from the train that just passed. It works for busways, not for trains. Put red lights on the busway to see how effective it really is.

HTG, what examples are you drawing on in your judgement about this? If the stations are spaced far enough, maybe this may not be such a problem... as Ozbob said, it may actually be designed in.

[petey3801]

Bifurcation required high frequency/very closely spaced signalling to work adequately, something we only have close to the city at this stage. It could be done, but would cost quite a large amount of money once outside the "inner city" area (ie: Darra, Northgate (possibly even petrie, caboolture line signalling is pretty good already), park road for cleveland line, moorooka for beenleigh line, bowen hills(!) for ferny grove line).

[#Metro]

Tramtrain, the bifurcation used for passing purposes does add about 2-3min to the station dwel time.

I think this is acceptable. Trains wait on the GC and FG (until duplicated) and yes while it was annoying, it would allow the express services to pass and more flexible timetable to be designed.

The thing that annoys me about the timetabling is that it isn't at all simple. There's single track, passing, flat junctions, signal spacing, curves, speed restrictions, trains that can't pass because the express ate up all the train path etc... all this severely limits capacity and putting on new services and expansion.

Consider a simple metro service on a simple line. More capacity? Just slot in another train. Over here we need to go into multiple months (or a year) analysing all the mathematical possibilities that have all the trains miss each other...

So IMHO simplicity is best... I guess Paris RER is the holy grail here.

[HappyTrainGuy]

TT, I'm basing it off what I've experienced in the past on the network with the currently signaling out of the city. On the old timetable there were trains frequently racing against each other (Still are) to get to certain parts of the network especially at Northgate, Bowen Hills, Southbank, Petrie and so on. The 7.22 Petrie-Ipswich express would often slow on the yellows from the 7.18 Petrie-Roma Street all stopper at Virginia. Another one that was always mixing up each other was the exp-Caboolture (Bowen Hills exp to Eagle Junction exp Northgate exp to Strathpine stopping all stations to Caboolture) train departed 3 minutes later than the Petrie all stopper but it wasn't until the Petrie train was departing Toombul/at Nundah that the Caboolture train actually passed by. The Petrie train would then be held/moving very slowly while the Caboolture train cleared the track ahead.

If you apply it to just the single track every time I catch an ex-Gold Coast train in the counter peak I'm always held up at Helensvale waiting for a train (~5.43-6.34pm Nerang dep seems to do it very very frequently). Ferny Grove line has done it aswell. The same with the few times I've used the Cleveland line this month being held up at a station waiting for the single track section to be clear.

So you want shorter dwell times, more doors for trains and faster trips yet would like to see infrastructure that supports longer dwell times and slower trips?

[#Metro]

So you want shorter dwell times, more doors for trains and faster trips yet would like to see infrastructure that supports longer dwell times and slower trips?

Well I think that's a loaded question. I really think that a 2 minute wait may not be as bad as having no service at all. That's the alternative... I wonder what the frequency will be for the Trouts Road corridor... hmm.... better not be 2 tph. The fact that this practice effectively already occurs and is accepted at places like Roma Street/South Bank/Central/Bowen Hills also sets a precedent.

[Golliwog]

So you want shorter dwell times, more doors for trains and faster trips yet would like to see infrastructure that supports longer dwell times and slower trips?

Well I think that's a loaded question. I really think that a 2 minute wait may not be as bad as having no service at all. That's the alternative... I wonder what the frequency will be for the Trouts Road corridor... hmm.... better not be 2 tph. The fact that this practice effectively already occurs and is accepted at places like Roma Street/South Bank/Central/Bowen Hills also sets a precedent.

But it's new infrastructure, surely we wouldn't build a new line and only run 2tph on it offpeak. Oh wait a second....


Couldn't resist that one.
But really I don't think it's that much of a loaded question, and I don't think the only alternative is no service at all, it just would be less express or a slower express.