Overtaking tracks at stations

[stephenk]

Moved from Members discussion:-

also i forgot to say but i was wondering why on new lines we dont build a slip lane for the station like the busways have so express trains can overtake?

That is commonly done in Japan. However it means that both all-stations and express services have to be running bang on time, something that QR have had issues with recently.

[stephenk]

Slip Lanes are quite a good idea, I can see them be exceedingly useful on the NCL.

The slip lanes are generally known as turnouts, although I'm sure there are other names for them (mainly in Japanese). Just to be confusing a turnout can also refer to points or switches in railway speak. They are very common in Japan (on suburban, interurban, and Shinkansen lines). Japan is the world leader in running an efficient rail service on minimal infrastructure.

The advantages of a turnout/overtaking track at specific stations re:-
- Less infrastructure costs than full triplication/quadruplication

The requirements and disadvantages of a turnout/overtaking track at specific stations are:-
- Both stopping or overtaking trains have to be running on time, or have similar lateness.
- The stopping train will have a longer running time as it has to wait a minute or so for the express to overtake.
- Good signalling headways are required around the site of the turnout/overtaking track.
- Timetabling has to take into account the turnout/overtaking tracks - generally this requires regular stopping patterns, as opposed to the current rather random timetables.
- Turnout/overtaking track at occasional stations would limit the frequency of each service pattern. More stations with turnout/ overtaking tracks would increase the number of possible frequencies, but decrease the infrastructure cost savings over a full triplication/quadruplication.

[Derwan]

Reposted from the members forum:

I think something like this is a potential way to stage future infrastructure.  For example, to cater for the increased traffic between Northgate and Petrie when the line to Redcliffe (and Sunshine Coast) is built, a forth track could be added - but the stations do not have to have platforms.  It could be an "express only" track utilised by trains to/from the North Coast and other expresses.  As stations become more popular and/or become part of a TOD, a forth platform could be added.

[Emmie]

Good idea, Derwan.  This system is used on the NYC subway system, and I'm sure it's nowhere near as efficient as the Japanese lines.  It has the added advantage that passengers transferring from an express to a local service at the express stations (say Northgate or EJ) don't have to change platforms, they just wait for the next local train to arrive.

[stephenk]

Reposted from the members forum:

I think something like this is a potential way to stage future infrastructure.  For example, to cater for the increased traffic between Northgate and Petrie when the line to Redcliffe (and Sunshine Coast) is built, a forth track could be added - but the stations do not have to have platforms.  It could be an "express only" track utilised by trains to/from the North Coast and other expresses.  As stations become more popular and/or become part of a TOD, a forth platform could be added.

If the Redcliffe line is built then I think we will need the cross river tunnel, a 4th track Northgate to Petrie, and 5th (or maybe even 6th) track Bowen Hills portal to Northgate. These extra tracks need to be built in a sensible configuration, unlike the current express track between Park Rd and Yerongpilly.

Good idea, Derwan.  This system is used on the NYC subway system, and I'm sure it's nowhere near as efficient as the Japanese lines.  It has the added advantage that passengers transferring from an express to a local service at the express stations (say Northgate or EJ) don't have to change platforms, they just wait for the next local train to arrive.

The NYC subway is a complicated system, which is not run as punctually as the Japanese rail system. Thus the tracks are not used to their full potential, and many of the express tracks are unused. If you are interested in the layouts they are here http://www.nycsubway.org/maps/track.html
Where there are 3 tracks, the express track is only used in the peak direction. 4 tracks allow expresses in both directions.

[brad C]

Another important and sometimes overlooked factor in ' speeding up' the systen through overtaking would be the track infrastructure and driver training.
High speed turnouts of at least 50kph would be required and improved driver training.
High speed turnouts of 80kph on the triplicated sections of the NCL are often ignored by drivers who slow and take these at 40 - 50kph.
In addition, sections prior to the junction indicator signals are set at double and single amber and some drivers start to apply the brakes as soon as the signals are spotted rather than looking beyond that to the junction indicator indicating the running path is actually clear.
An then there are the 25kph crossovers closer to town which often means that an express service  takes longer between say wooloowin and bowen hills than a parallel running all stopper. One hopes that if the old mayne yards are ever sold to developers that the lines can be realigned in that location which could effectively shave 2 minutes from a section.

Much to contemplate!!

[#Metro]

I know that in Melbourne, trains disappear into tunnels, while some stay on the surface. I can't remember whether it was Parliament Station or Flagstaff, but one of the stations has two underground levels (the whole station itself being underground). The tunnels are practically stacked above each-other.

Perhaps to relieve congestion, Ipswich line trains could disappear into a tunnel before reaching Roma St. A new set of platforms would be carved out underneath the existing ones, to create a two level station. The same could be done for Central, Fortitude Valley and Bowen Hills.

I know this could sound expensive, but hey, the tunnel machines are here already and the benefits may well outweigh the costs. Alternatively, express services could use the tunnel levels, while all stations could use the above ground ones...

[stephenk]

I know that in Melbourne, trains disappear into tunnels, while some stay on the surface. I can't remember whether it was Parliament Station or Flagstaff, but one of the stations has two underground levels (the whole station itself being underground). The tunnels are practically stacked above each-other.

Melbourne has 4 underground loop tracks (although the underground tracks are only 1/2 of the loop, the other half being the existing surface tracks). Melbourne's lines are split into 4 groups. Each group uses 1 loop track. The tunnel portals are designed so that trains can enter or exit each loop track without conflicting movements with other tracks. It should be noted that Melbourne's railways actually ran a higher frequency before the loops!

Perhaps to relieve congestion, Ipswich line trains could disappear into a tunnel before reaching Roma St. A new set of platforms would be carved out underneath the existing ones, to create a two level station. The same could be done for Central, Fortitude Valley and Bowen Hills.

I know this could sound expensive, but hey, the tunnel machines are here already and the benefits may well outweigh the costs. Alternatively, express services could use the tunnel levels, while all stations could use the above ground ones...

This is pretty much what is planned with the Cross River Rail project (or whatever it's called this week), except the underground tracks may be on a new alignment to serve new areas such as the Gabba and Gardens Point. The first new tunnel will take pressure off the suburban tracks (Gold Coast/Beenleigh/Cleveland) as opposed to the main tracks (Ipswich Line) which has slightly more spare capacity. The first stage will cost over $8b!