General Speed Degradation and Erosion in QR Timetables

[#Metro]

Discussion from the Toowoomba thread links to a 1988 version of QR timetables (internal). An interesting thing to do is compare that to todays timetables and see if speeds are similar or different.

Since 1988, the Ipswich motorway opened (1994) and was upgraded a number of times. If we want PT mode share to grow, rather than just hold or slowly fall, then average speed needs to be maintained or improved...

QR 1988 Timetable (internal)
https://undertheclocksblog.files.wordpress.com/2021/12/qr88whole.pdf

Ipswich Line Speed Degradation

Page 31 of the 1988 QR Ipswich Line timetable (internal) show Service 1502 departing Roma Street at 5.14 am and arriving at Ipswich at 6.01 am, an all-stops journey time of 47 minutes.

The same times are listed for Service 1504 (Page 32), Service 1506 (Page 33). So this seems to be a typical speed.

The general running time for an all-stops service to Ipswich today is 56 minutes (August 2020 timetable).

That's a nine minute loss compared to 1988.

Even express trains today take 48 minutes, one minute longer than all-stops trains to Ipswich in 1988 (Express Milton to Darra, exclusive)

Today's 'express' trains between Milton and Darra only save about 8 minutes.

The average speed between Roma Street and Ipswich has therefore dropped from 48.37 km/hr in 1988 to 40.59 km/hr today. The Ipswich Motorway opened in 1994.

Questions:

* If we were to combine express running with a faster track, would it be possible to get a limited express service to Ipswich within 39 minutes from Roma Street?

* What caused the slow down?

* What potential works would bring line speed back up?

[HappyTrainGuy]

Capacity through the inner core and their crosses at Roma Street. All services stop at Milton to have a unified flow into Roma street ie P9 services stop and an P8 services instantly crosses after. P8 is occupied so as as an P9 service is coming in at the same time a P10 service is crossing in front of P9 which means the P9 service enters the platform at reduced speeds due to the red at the central platform end. Even spacing so you're not following on yellow or double yellow. Extra stations (depends on the line). DDA. Back in the day disabled passengers slowed services quite a lot. Fat in the timetable. You could add in rollingstock but it's only a few seconds here and there. EMU's had brutal close rates back in the day. The current timetable is also based on peak hour running. Timetables back in the day had off peak and peak hour times. Now you can have full peak hour trains with footy fans getting off at Milton and you only lose 4 mins into Roma street but back on time by Northgate. Level crossing timing points ie Sherwood. You also had short haul services such as Darra and Redbank services. Those are the main reasons for slow downs in the timetables.

Just so you know Metro your calculation is based on a flawed timetable that has a large amount of fat added to slow the trains down and have crosses to minimise level crossing downtime. South of Beenleigh your time also increases due to the speed.

I'll use the Darra example. Green track running Darra-Roma Street is 14min30sec. Express stopping at Milton and Indoorpilly is 18min and 26min for the all stopper. The only reason express trains stop at Milton is to even the flow of trains arriving into Roma street along with the terminators from the north.

[JimmyP]

Plus, by what I have been told, trains were actually required to break the speed limits in order to maintain the timetables back in the 80s and 90s, as the timetables were so tight. 10% overspeed was the norm on most lines.

Definitely agree the speeds need to be increased, best achieved by infrastructure improvements for the most part. Express services work well but the other stations still need good frequent services, and there is only so much capacity available.

Unfortunately, realignments are difficult inbound of Darra without tunnels and/or resumptions (granted, resumptions are made all the time for roads...). There is a lot of 50-60km/h running between Darra and Roma Street unfortunately.

[HappyTrainGuy]

Not true. If you were caught speeding you'd be in trouble. There were people who would manually record your speed onboard the train. Sometimes they'd enter via an unused cab or manually record time between speed boards. Counter peak you will find a lot of trains on the subs doing nothing which limits your capacity and how it's run compared to years previously. There were also larger gaps in the timetable so you didn't have the issues of following on restricted signals which we have now in some instances. For example the arvo Sherwood crosses. You have a citybound stopping/citybound deadrunner on the mains, an all stopper stopped on the subs, an express to Ipswich on the mains and a dead runner coming off the Tennyson loop onto the subs (that will be held between Milton-Roma street on the subs and slots in behind the same all stopper that it overtook at Sherwood) at the same time. Same with morning peak with dead runners being held outside Sherwood and dead runners from Tennyson/southern lines waiting at Corinda. Even on the mains for that matter it's gets congested. Services terminating at Kuraby or Park Road return on the western lines via Tennyson loop.

There are quite a lot of 100kph speed boards too. As I have mentioned Darra-Roma Street is a 15 minute run in a perfect world. It's why late running express trains can be 10 mins late at Darra and go into central nearly back on time. If there is a delay tomorrow and express services go true express look how much time they make up on the Darra-Roma street leg. Add in extra stops for express stoppers and even spacing and you are close to 20 mins. Add in all stoppers and you are border line 26 mins.

[JimmyP]

Obviously not officially condoned/required to speed, but having spoken to many drivers from that time, 10% overspeed was pretty normal to keep to time in days gone by.

Also, very few 100km/h sections inbound of Darra. Used to be 100 through Graceville both ways, but only outbound now (inbound is 90 now), and inbound between Taringa and Toowong for approx 1km (outbound 90). So about 2km (give or take a couple hundred m) between Darra and Roma St. A few 80 sections here and there, but a lot of 50 and 60, according to current drivers out there.

Definitely a few minutes of fat in the current timetable though as well, especially with the expresses.

[#Metro]

RBOT Facebook Page Feedback (anonymised)

The least that could be done is a 'desktop' study into average train speed degradation over time, and then an appraisal of potential improvements.

Motorways are built to very high, uncompromising standards - 100 or 110 km/hr. If there is topographic or terrain in the way, earthworks and engineering works are brought in. Road cuttings or elevation is put in so that the standard is met and maintained. Grade separation of junctions.

Nobody seems to question any of that. It is just expected and accepted.

For rail, not the same approach. Much less enthusiasm to engage and undertake works, even though the line capacity is much higher than for a road lane, particularly during peak. (Road lane = 2160 pphd in peak, train much higher than this). Flat junctions all over the place.

Cars will continue to be the preferred mode so long as PT offers a slower overall door-to-door service. Trains are capable of much higher speeds than cars but this potential is being left on the table and not fully realised.

From the RBOT FB page (public)
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