I went for a ride out to T.T.P. last weekend for the first time in ages and I noticed the corrugations in the track are still quite bad despite DPTI saying they've been taken care of (track grinding). Perhaps it was just the bus I was on but there were really noticeable vibrations on the up track just after Klemzig, again after Paradise and then again just before T.T.P. My bus was very new so I don't think you could blame it on any mechanical problem to do with the guide wheels.

Departing Paradise it was really very noticeable, like being on a country road. Is it possible the corrugations have re-emerged after grinding down or were they never fixed properly to begin with? Considering the concrete track was only projected to have a 30-year life perhaps it can't actually be fixed properly.


Thoughts?

I have ridden the obahn a couple of times in the last few months and not noticed this.

The OP is even more relevant if it is edited to read:

I went for a ride out to Seaford last weekend for the first time in ages and I noticed the corrugations in the track are still quite bad despite DPTI saying they've been taken care of (rail grinding). Perhaps it was just the train I was on but there were really noticeable vibrations on the up track just after Noarlunga, again after Christie Downs, again after Lonsdale, again after Hallett Cove Beach, again after Hallett Cove, again after Marino Rocks, again after Marino, again after Seacliff, again after Brighton, again after Hove, again after Warradale, again after Oaklands, again after Marion, again after Ascot Park, again after Woodlands Park, again after Edwardstown, again after Emerson, again after Clarence Park, again after Goodwood, again after Adelaide Showground, again after Mile End, and then again just before the 15km/h limit a kilometre out from Adelaide. My train was very new so I don't think you could blame it on any mechanical problem to do with the - actually, you can blame it at least partially on the trains which ride horribly.

Departing Seaford Meadows and crossing the Onkaparinga River it was really very noticeable, like being on a country road. Is it possible the corrugations have re-emerged after grinding down or were they never fixed properly to begin with? Considering DPTI think concrete sleepered track can have a 30-year life without maintenance, perhaps it can't actually be fixed properly.

The O-Bahn is holding up just fine.

At some point there will need to be a track replacement program commenced, just like there would be on any rail line or road which carries anywhere near the same level of traffic. Replacing a few segments on one track every Sunday should do the job, and perhaps keep a crew in permanent enough part time work that once finished they could then immediately swap over to the next big rail track rebuild which could have been averted by conducting regular night/weekend maintenance.

Now that I have noticed JAP!

I have ridden the obahn a couple of times in the last few months and not noticed this.

It could have been some other sort of resonance but it seemed to me that it was corrugation; it was just like a car on a corrugated dirt road.

Funnily enough I didn't notice anything on the down trip, it seemed to be confined to the "up" track which makes me think now that it may have been the individual bus I was on (ie not all buses get resonance?). Anyway just an observation.

At some point there will need to be a track replacement program commenced, just like there would be on any rail line or road which carries anywhere near the same level of traffic...

I can't imagine this will be an easy or cheap thing to do. Granted, it's a modular system whereby they can probably replace the individual sections of track with new parts and simply drop them in - but they're pretty large pieces of reinforced concrete and it's been a long time since they've been purpose-built for the OBahn.

Has the patent/proprietary technology been opened up yet, does anyone know?

Now that I have noticed JAP!

It's a few weeks since I last rode a Seaford/Tonsley train into town, do you know if they have fixed that track defect with the 15km/h speed restriction just north of Sir Donald Bradman Drive?

Granted, it's a modular system whereby they can probably replace the individual sections of track with new parts and simply drop them in - but they're pretty large pieces of reinforced concrete and it's been a long time since they've been purpose-built for the OBahn.

They are about to be purpose built once again for the O-Bahn extension, so it would make sense to keep on producing more of them if a track replacement program is coming up - even if it's just for the bits in acceleration and braking zones.

It's been interesting to note the switch from highly specialised rail equipment to road-rail adapted trucks with many of the recent projects. I'm sure there are some soon-to-be-unemployed engineers at Holden who would love to be paid to work out a solution applying the same principle of adapting otherwise standard equipment to work with the guideway.

Has the patent/proprietary technology been opened up yet, does anyone know?

The patent would definitely have expired by now. If the manufacturer were to demand royalties or a hefty price for handing over the plans, it would be legal to design a replacement by reverse-engineering.

The track itself is fine. It's the buses that were ordered (to replace the old high floors which were reaching their life limit) that were not modified for O'bahn use. The axles are the problem. I find it worst when sitting at the front of an artic (sometimes I need to due to a loud noise from the back related to a mechanical issue).

They are terrible buses overall.

They are about to be purpose built once again for the O-Bahn extension, so it would make sense to keep on producing more of them if a track replacement program is coming up - even if it's just for the bits in acceleration and braking zones.

Section 23.3 of the project impact report http://www.infrastructure.sa.gov.au/__data/assets/pdf_file/0005/175370/Project_Impact_Report_-_Section_D_-_Construction_And_Staging_Concept_Design_Guidelines.pdf lists several alternative forms of construction for the guided busway section in the tunnel but seems to favour a concrete slab with kerbs to allow access for emergency vehicles over the existing modular construction.

Alex C

Now that I have noticed JAP!

It's a few weeks since I last rode a Seaford/Tonsley train into town, do you know if they have fixed that track defect with the 15km/h speed restriction just north of Sir Donald Bradman Drive?

Just over three weeks ago there didn't seem to any evidence of a restriction at Mile End

Alex C

The track itself is fine. It's the buses that were ordered (to replace the old high floors which were reaching their life limit) that were not modified for O'bahn use. The axles are the problem. I find it worst when sitting at the front of an artic (sometimes I need to due to a loud noise from the back related to a mechanical issue).

They are terrible buses overall.

Sounds like the most likely explanation.

The track itself is fine. It's the buses that were ordered (to replace the old high floors which were reaching their life limit) that were not modified for O'bahn use. The axles are the problem. I find it worst when sitting at the front of an artic (sometimes I need to due to a loud noise from the back related to a mechanical issue).

They are terrible buses overall.

Sounds like the most likely explanation.

The older buses were much better suited. The Mercedes 0305's were built with reinforcements and upgraded brakes for O-bahn use. When the time came for replacement, Mercedes wanted too much for suitable vehicles (and I believe they would have been fully imported, instead of chassis with local bodies). There was testing with Volvo and Scania chassis under IIRC Volgran bodywork. Both were dismal failures, but Scania offered to modify the chassis for much less than anyone else. Hence the Scania's being purchased to replace the 0305's. Most of the new low floor buses actually aren't going to last the entire 25 year state limited lifespan, as they're just not built strong enough. So they'd probably already be falling apart with the strain of regular high speed running on the O-bahn.

The buses are already shaking themselves apart. There are numerous threads on the ATDB about the Scania K series and their inability to run on the O-Bahn. It has nothing (or very little) to do with the track itself, it's in pretty good condition.
Scania K-Series in Adelaide (ATDB)
There are also other topics to find if anyone is really interested.

A good thread to watch where buses' faults are recorded:
Motor Melodies and Maladies

I'll check up out Mile End tomorrow JAP, I am in the unenviable position of being required to make the journey there...