Buses on rail signalling?

[Rhydgaled]

Sitting in the 1.3mile traffic jam again on the bus on my way into Aberystwyth this morning. Somebody in front of me said to their friend that something needs to be done about this. This got me thinking (again) about a new Carmarthen-Aberystwyth railway and in particular my idea of using the last bit into Aberystwyth as a bus-only road until (if) the case for the new railway is made.

The question in my mind was what would happen to the bus service if/when the railway is built. Then I thought, trains and buses can both run over level crossings without a problem, so could you set the rails in the tarmac of the bus-only road and have buses and trains share the same alignment? I assume you would employ rail-signaling-like methods to ensure there is only one bus or train in the section at a time, is this possible/feesible?

 

[TheGrandWazoo]

Sitting in the 1.3mile traffic jam again on the bus on my way into Aberystwyth this morning. Somebody in front of me said to their friend that something needs to be done about this. This got me thinking (again) about a new Carmarthen-Aberystwyth railway and in particular my idea of using the last bit into Aberystwyth as a bus-only road until (if) the case for the new railway is made.

The question in my mind was what would happen to the bus service if/when the railway is built. Then I thought, trains and buses can both run over level crossings without a problem, so could you set the rails in the tarmac of the bus-only road and have buses and trains share the same alignment? I assume you would employ rail-signaling-like methods to ensure there is only one bus or train in the section at a time, is this possible/feesible?

Bus and trams do share the road in many UK and European cities so rails in the road are not an issue.

However, heavy rail is generally segregated. There used to be instances such as the Weymouth ferry train where the train would be sent onward from Weymouth station through the streets (rails are still there) and to the ferry terminal. This practice stopped c.1992 for commercial and safety reasons.

Mind you, it's academic. The rail line between Carmarthen and Aber WILL NOT BE REINSTATED. There are much more likely and appropriate schemes to reinstate old lines that have a much better business case.

 

[Rhydgaled]

heavy rail is generally segregated
...
for commercial and safety reasons.

I thought the lack of street running for heavy rail was for safety reasons. That's why I'm intrested in whether you could do it if the road vehicles (buses) obeyed rail signalling, would this work and would it be safe enough?

Mind you, it's academic. The rail line between Carmarthen and Aber WILL NOT BE REINSTATED. There are much more likely and appropriate schemes to reinstate old lines that have a much better business case.

I did say if. Personally, I think new lines Bangor - Porthmadog and Newtown - Brecon - Cardiff should be higher priority than Carmarthen - Aberystwyth if buses can be made suitably attractive on the latter corridor. However, it is a Carmarthen-Aberystwyth line that I keep seeing petitions for.

Out of interest, do you think a bus-only road (designed to be a suitable rail alignment) from Llanfairian into Aberystwyth would have a decent case?

 

[CatfordCat]

I'm not a signalling engineer, and know nothing about the route involved, but the issues that come to mind immediately -

On the Weymouth Quay line, and one or two goods lines I can think of that had street running, trains had to run at very low speeds (walking pace or thereabouts)

The risk of collision between a bus and a full size train running at speed is really not something that takes much imagination. Buses do not have buffers etc to withstand even a low speed impact.

I can't think of a way that buses would easily trigger track circuit detectors which is an important part of modern train signalling.

The risk of a bus veering a few inches off a true path and colliding with an oncoming train is high. Two train tracks can be set so that there's only a small clearance between two trains going in opposite directions, but there's little chance of a train driver not steering correctly. Guided bus might overcome this, but not sure the technology is there for 'guide by wire' to work yet - and I don't think that kerb-guidance would be compatible with rail technology.

 

[Rhydgaled]

I can't think of a way that buses would easily trigger track circuit detectors which is an important part of modern train signalling.

That's the sort of information I'm looking for. Issues like that, and whether anyone can think of a way of getting round them?

The risk of a bus veering a few inches off a true path and colliding with an oncoming train is high. Two train tracks can be set so that there's only a small clearance between two trains going in opposite directions, but there's little chance of a train driver not steering correctly. Guided bus might overcome this, but not sure the technology is there for 'guide by wire' to work yet - and I don't think that kerb-guidance would be compatible with rail technology.

Another interesting point. In the specific example I was only envisioning a single track line, perhaps with buses only using the route in the peak direction. Would some form of token working system be workable?

 

[TheGrandWazoo]

That's the sort of information I'm looking for. Issues like that, and whether anyone can think of a way of getting round them?

Another interesting point. In the specific example I was only envisioning a single track line, perhaps with buses only using the route in the peak direction. Would some form of token working system be workable?

Being brutally honest, there is no likelihood of either the rail line returning nor the introduction of any bus only road a la South Hampshire's Eclipse. Look at how many places have them in the UK, and then look at the likelihood of somewhere with a small population like Aber getting that type of investment.

The lines you're picking out are never, ever going to happen. The sheer cost of reinstating lines is phenomenal and the benefits very modest. More likely is the use of existing freight lines for passenger use.

 

[notadriver]

Sitting in the 1.3mile traffic jam again on the bus on my way into Aberystwyth this morning. Somebody in front of me said to their friend that something needs to be done about this. This got me thinking (again) about a new Carmarthen-Aberystwyth railway and in particular my idea of using the last bit into Aberystwyth as a bus-only road until (if) the case for the new railway is made.

The question in my mind was what would happen to the bus service if/when the railway is built. Then I thought, trains and buses can both run over level crossings without a problem, so could you set the rails in the tarmac of the bus-only road and have buses and trains share the same alignment? I assume you would employ rail-signaling-like methods to ensure there is only one bus or train in the section at a time, is this possible/feesible?

Wouldn't rail rules and signalling be too complicated for bus drivers to understand ?

 

[34D]

Would surely be no different to trams and buses sharing lanes in Sheffield and Manchester?

 

[notadriver]

Would surely be no different to trams and buses sharing lanes in Sheffield and Manchester?

Interesting. I assume those sections are 30 mph maximum and driven line on sight ?

 

[1e10]

Would surely be no different to trams and buses sharing lanes in Sheffield and Manchester?

Does the Metrolink in Manchester have signals?

 

[martin2345uk]

Does the Metrolink in Manchester have signals?

Conventional rail signals on older segregated sections, modern tram signals on newer and shared alignments.

 

[notadriver]

Block signalling is needed for trams on the higher speed (30 mph+) sections right ? If so a bus would need equipment to stop or entering an occupied section.

 

[martin2345uk]

Block signalling is needed for trams on the higher speed (30 mph+) sections right ? If so a bus would need equipment to stop or entering an occupied section.

No, they are slowly removing the block signalling completely. 50mph is the top speed on line-of-sight (ie minimal signalling) sections.

 

[notadriver]

What so two trams can follow each other 100 metres apart at up to 50 mph ?

 

[martin2345uk]

What so two trams can follow each other 100 metres apart at up to 50 mph ?

Well I'm sure there are rules for drivers how close they should get but yes in theory, there would be nothing to stop this on most segregated sections.

 

[notadriver]

Well I'm sure there are rules for drivers how close they should get but yes in theory, there would be nothing to stop this on most segregated sections.

Agreed I'm just reading up - and this seems to be the case on Metrolink and would be no different to the buses on the Cambridge guided busway driving on line of sight at up to 55 mph.

It does mean that despite using a reserved section drivers would have to reduce speed where a bend reduces visibility or in foggy weather. This differs from traditional heavy rail.

 

[edwin_m]

Wouldn't be as close as 100m at 50mph as they would need to use emergency brakes if the tram in front stopped suddenly. But it is possible for trams to operate safely much closer together than trains and on straightish sectione the train in front would clearly be visible.

The difficulty around a shared signalled section is probably to do with proving that there are no buses occupying it before the signals are cleared for a train. As suggested buses do not operate track circuits and any system to detect a bus would have to be absolutely reliable against "false positives", because of the serious consequences for the occupants of the bus if it was hit by a train. Something like a light beam could be triggered falsely by, for example, a newspaper blown in the wind. Systems such as ANPR or transponders, as used to operate things like car park barriers and tram signals, are not designed to the same high integrity as railway signalling.

 

[notadriver]

If speeds are limited to 50 mph and line of sight used trams and buses then it will work.

But trains cannot be operated in this way.

 

[1e10]

The Metrolink trams seem to be able to accelerate and brake harder than trains too.

 

[notadriver]

The Metrolink trams seem to be able to accelerate and brake harder than trains too.

Oh most definitely thats why it can work with trams and buses at 50 mph using line of sight. Trams also have magnetic brakes. I think metrolink trams can probably out accelerate a modern bus

 

[AnonymousUser1]

<snip>

The risk of a bus veering a few inches off a true path and colliding with an oncoming train is high. Two train tracks can be set so that there's only a small clearance between two trains going in opposite directions, but there's little chance of a train driver not steering correctly. Guided bus might overcome this, but not sure the technology is there for 'guide by wire' to work yet - and I don't think that kerb-guidance would be compatible with rail technology.

although speeds are low wire guided technology is very well developed in warehousing - it is one of the reasons why the 'very narrow aisles' are only inches wider than the lift trucks that run in them

 

[edwin_m]

Wire guidance is indeed proven, having been used for the Channel Tunnel service tunnel. It was installed on the busway serving the Millennium Dome but as far as I know never used in service - the road was wide enough to drive on without guidance so there probably wasn't much point. There is some risk of a loss of guidance due to system failure or ice on the running surface (wire guidance system would still work but bus might not be able to steer to follow it).

I'm pretty sure the geometry of kerb guidance is incompatible with running a train on the same track.

 

[Rhydgaled]

Sounds like a no then.

Nobody seems discussed whether token working (I think there's a system called something like 'electric token' where there are multiple tokens but only one can be removed) could be modified to work with buses and whether it would resolve the issues. How about a button the driver has to push, if the route is clear a barrier raises to allow access, if not the barrier stays shut. There's a barrier between the university and National Library in Aberystwyth that opens for the bus without even having a button to press to open it, not sure how it works though.

 

[notadriver]

I believe trams and buses can work but the alignment would need to be widened like a normal 'A' road (train tracks take up less width than a road) or install a guideway for buses (expensive). Trams seem to have equivalent accelerating and braking performance to buses but someone feel free to correct me.

 

[Rhydgaled]

Why all the comments about trams? I know they can share roads with buses. What I am trying to do is work out whether buses and trains could share an alignment so both can benifit from construction of a new route.

 

[90019]

There's a barrier between the university and National Library in Aberystwyth that opens for the bus without even having a button to press to open it, not sure how it works though.

It probably uses ANPR, with a database of the plates on all the buses that use it.

 

[notadriver]

Why all the comments about trams? I know they can share roads with buses. What I am trying to do is work out whether buses and trains could share an alignment so both can benifit from construction of a new route.

Fine I will unsubscribe from the thread.

 

[CatfordCat]

It probably uses ANPR, with a database of the plates on all the buses that use it.

That's possible (as is remote operation via CCTV from the security office)

If the route has real-time information, then the GPS kit on the bus can trigger bus priority measures (such as traffic signal phase requests, opening barriers etc)

Some form of electronic tag fitted to the bus, that's read by something either roadside or under the road surface is possible, although that's a bit old hat now.

Or it may work on 'approach control' (i.e. any vehicle driving on to the detector loop would trigger it) - although anyone who installs a system like that tends to keep quiet about how it works. You can car-proof it a bit by making the detector long enough only to register if there's a vehicle longer than X metres on the detector loop - although two cars together can fool such systems.

 

[edwin_m]

As I posted before, given the horrendous potential consequences of a train-bus collision, ANPR and tag systems are not considered reliable enough to prove a shared section is clear of buses before a train is allowed onto it.

 

[ECML180]

It probably uses ANPR, with a database of the plates on all the buses that use it.

Much better system on a bollard bus gate here, the driver has a smartcard that he touches on a sensor just prior to the bollard.

Being such a good system it necessitates a stop(to tap the card and allow the bollard to drop) and also a 2 foot long piece of wood & sticky tape as the road curvature prevents the driver from being near the curb and the post

I don't see why considering trams is an issue? Tram-trains may be a better term but removing the rail signalling and operating both rail and road vehicles on line of sight principal solves the problem as far as I can tell!