Lines where ATO could work

[Bald Rick]

I think the two most likely schemes for ATO within the next 5 years would be Norhern city line between Drayton Park to Moorgate and as mentioned earlier the ELL core between Surrey Quays and Highbury & Islington.

Correct, both have been awarded initial funding, I read that in Modern Railways I think.

In both cases it enables more services.

 

[jyte]

Greater Glasgow definitley in the next 20 or so years.

Watford DC line could be another candidate.

Correct me if I'm wrong but doesn't the DC line only have 3tph atm?

 

[MarkyT]

Correct me if I'm wrong but doesn't the DC line only have 3tph atm?

There's also inter-running with the Bakerloo Line beyond Queens Park. Higher frequency thus applies as far as Harrow & Wealdstone. Whatever kind of signalling and ATO is provided in the future it will have to be compatible with both train fleets and the Overground stock will also have to be remain AWS/TPWS compatible for working into Euston (and ETCS in the future).

 

[A Challenge]

Or perhaps Metrolink outside of the street running sections.

With driverless cars why only off-street?

 

[Mathew S]

With driverless cars why only off-street?

True. That's a good way off though I think.

 

[trainmania100]

Could upgrade the 483s on island line, or use existing expired tube stock with ATO. After all, it's only a short line and probably be cheaper to upgrade existing stock that buy a load of teams and regauge tunnels etc for new stock

 

[philthetube]

Greater Glasgow definitley in the next 20 or so years.

Watford DC line could be another candidate.

Will happen south of Harrow for certain, for the Bakerloo, whether overground services will go ATO is another question, having them run into Euston would be an issue, probably easier to operate in the same way as the north end of the Met is going to operate with the Met and Chiltern.

 

[MarkyT]

Will happen south of Harrow for certain, for the Bakerloo, whether overground services will go ATO is another question, having them run into Euston would be an issue, probably easier to operate in the same way as the north end of the Met is going to operate with the Met and Chiltern.

Presumably the Chiltern DMUs will be modified to provide SelTrac cab signalling and ATP for the shared sections. It may be full ATO is too tall an order for these older trains. I wonder if it might be easier to modify S-stock to also handle ETCS and equip the shared sections with some form of that, or even just AWS/TPWS (suggestion only slightly tongue in cheek!)

A native ETCS train might be able to deal with SelTrac by means of STM (specific transmission module) functionality. That's how modern trains such as the 700s cope with legacy protection systems such as UK AWS and TPWS. If the system being emulated is also balise-based, like French KVB, Belgian TBL 1+, Swiss EuroSignum/ZUB, and the new variant SelTrac being used on TfL's Four Lines, then the balises might even be able to to be interrogated by the standard eurobalise reader and antenna hardware.

This is a good read on the capabilities of ETCS to implement alternative (usually legacy) protection schemes, known as Class B systems.
https://en.wikipedia.org/wiki/European_Train_Control_System#Alternative_implementations

 

[Bald Rick]

Presumably the Chiltern DMUs will be modified to provide SelTrac cab signalling and ATP for the shared sections. It may be full ATO is too tall an order for these older trains. I wonder if it might be easier to modify S-stock to also handle ETCS and equip the shared sections with some form of that, or even just AWS/TPWS (suggestion only slightly tongue in cheek!)

A native ETCS train might be able to deal with SelTrac by means of STM (specific transmission module) functionality. That's how modern trains such as the 700s cope with legacy protection systems such as UK AWS and TPWS. If the system being emulated is also balise-based, like French KVB, Belgian TBL 1+, Swiss EuroSignum/ZUB, and the new variant SelTrac being used on TfL's Four Lines, then the balises might even be able to to be interrogated by the standard eurobalise reader and antenna hardware.

This is a good read on the capabilities of ETCS to implement alternative (usually legacy) protection schemes, known as Class B systems.
https://en.wikipedia.org/wiki/European_Train_Control_System#Alternative_implementations

I thought the new Met line signalling was going to be ‘underlaid’ with conventional lights on sticks for the Chiltern services.

 

[gsnedders]

I thought the new Met line signalling was going to be ‘underlaid’ with conventional lights on sticks for the Chiltern services.

Yes, this is my understanding too. The shared sections will be operable with lights-on-sticks (with obviously much larger signal blocks than the few meters for the SelTrac system).

 

[MarkyT]

I thought the new Met line signalling was going to be ‘underlaid’ with conventional lights on sticks for the Chiltern services.

Yes, this is my understanding too. The shared sections will be operable with lights-on-sticks (with obviously much larger signal blocks than the few meters for the SelTrac system).

On the shared section, frequencies are not particularly high with the Met running most of the day all stations on the slows leaving the fast tracks the sole domain of the DMUs, so perhaps the longer fixed blocks will be suitable for all traffic, with SelTrac just providing ATP and ATO overlay for the fast Met trains during the peaks. The Chiltern DMUs would presumably use their AWS and TPWS?

 

[swt_passenger]

I thought the new Met line signalling was going to be ‘underlaid’ with conventional lights on sticks for the Chiltern services.

Yes, here’s a fairly recent summary from Rail Engineer mag. No standard solution:

Interworking with other lines

Shared operation with other lines and train services has been referred to. On most of these – from Chiswick Park to Hanger Lane (where the District line uses Piccadilly line track), London Overground from Gunnersbury to Richmond, South West Railway from Putney to Wimbledon – the SelTrac system will be overlaid on to the existing conventional signalling on these sections such that ATO can be maintained. The ATO overlay will align with the block sections of the conventional signalling so not all CBTC features, such as moving block, will be possible. However on these extremities, this is not seen as a problem since the service density is lighter.

On the Chiltern Lines from Harrow on the Hill to Amersham and Piccadilly line from Rayners Lane to Uxbridge, an ‘underlay’ system is being provided, whereby the present signalling is being replaced with a conventional three-aspect system for Chiltern trains but incorporating a blue aspect for Metropolitan line trains working in ATO mode.

The system will know which type of train is where and will display the appropriate aspect on the signal. The system will not show a blue light when either a red, yellow or green aspect is displayed and vice versa. This ‘underlay’ approach will allow following Metropolitan line trains to operate in moving block operation whilst Chiltern Line and Piccadilly line trains will remain in fixed block operation.

https://www.railengineer.uk/2018/01/11/training-for-4lm-is-under-way/

 

[MarkyT]

The system will know which type of train is where and will display the appropriate aspect on the signal. The system will not show a blue light when either a red, yellow or green aspect is displayed and vice versa. This ‘underlay’ approach will allow following Metropolitan line trains to operate in moving block operation whilst Chiltern Line and Piccadilly line trains will remain in fixed block operation.

That definitely makes sense for Rayners Lane - Uxbridge, but moving block on the fasts beyond Harrow-on-the-Hill seems to me like overkill for the traffic. I'm sure Richmond and Wimbledon are much busier. For full moving block the new SelTrac needs digital balises, or 'tags' as they seem to call them now, every few tens of metres (these replace the old continuous leaky feeder cable pair transpositions as used on the Jubilee, Northern and DLR for position calibration). The continuous movement authority is maintained by radio, which on the 4 track sections can probably be shared with the busier slow lines I guess.

 

[Railperf]

ATO seems to work best on lines with a single type of traction, very short headways between trains and where you need consistent running performance.
In ordinary conditions where there train ahead is far enough ahead to avoid unnecessary checks, the station to station run times are almost identical compared to what you would achieve if they were manually driven.
But on a line with low traffic such as the Gospel Oak to Barking line for instance - there is no point implementing ATO because the service frequency is too low, and so a cautiously driven train is not going to impact on the trains behind. But on a service where a train is running 2 to 3 minutes behind another, there seems to b a requirement for very consistent journey times. No point having drivers that are losing time, and others that are catching up the trains ahead. ATO seems to regulate that really well. I'm not sure were the maths stack up to say that a headway of 3 minutes or less is the point that ATO is preferable to manual driving. Does anyone know this?

I.E i was using the london Underground Central Line recently, and the station to station run times in very wet weather were remarkably consistent with those achieved in the dry weather. That's because the trains computers can more accurately pinpoint braking points and retardation rates. Not to say that there aren't drivers who can 'beat' or match the computer - because I am sure there are. But drivers will on the whole be more cautious in the wet to avoid a SPAD, whereas the computer does what it is programmed to do. On a couple of occasions in fact the trains ended up stopping way too short and had to be restarted to the correct platform stopping position.

 

[philthetube]

ATO seems to work best on lines with a single type of traction, very short headways between trains and where you need consistent running performance.
In ordinary conditions where there train ahead is far enough ahead to avoid unnecessary checks, the station to station run times are almost identical compared to what you would achieve if they were manually driven.
But on a line with low traffic such as the Gospel Oak to Barking line for instance - there is no point implementing ATO because the service frequency is too low, and so a cautiously driven train is not going to impact on the trains behind. But on a service where a train is running 2 to 3 minutes behind another, there seems to b a requirement for very consistent journey times. No point having drivers that are losing time, and others that are catching up the trains ahead. ATO seems to regulate that really well. I'm not sure were the maths stack up to say that a headway of 3 minutes or less is the point that ATO is preferable to manual driving. Does anyone know this?

I.E i was using the london Underground Central Line recently, and the station to station run times in very wet weather were remarkably consistent with those achieved in the dry weather. That's because the trains computers can more accurately pinpoint braking points and retardation rates. Not to say that there aren't drivers who can 'beat' or match the computer - because I am sure there are. But drivers will on the whole be more cautious in the wet to avoid a SPAD, whereas the computer does what it is programmed to do. On a couple of occasions in fact the trains ended up stopping way too short and had to be restarted to the correct platform stopping position.

This is because the train braking is exactly the same wet or dry, In very bad conditions sometimes drivers have to take over

The stopping in the wrong place is generally restricted to the central line, it is not normally a problem on the Jubilee or Northern,

As far as resignalling goes the current stuff has to be replaced anyway so probabbly not that much cost to do it anyway.

 

[jyte]

If I remember correctly the Central lines ATO system has a 'low adhesion' option built into the deceleration profile that can be switched on in sections from the control room.

 

[HSTEd]

Shinkansen studies indicated that any water on the railhead (be it as water or ice) is gone by about the eighth or tenth axle to pass over it.
From that point on adhesion is the same regardless as the water has been pushed off the railhead or evaporated.

Given taht a normal shinkansen set has 64 axles.... this means it is not an issue.
Then again Japanese rail companies have experimented with air brakes for Shinkansen sets.

 

[Railperf]

Shinkansen studies indicated that any water on the railhead (be it as water or ice) is gone by about the eighth or tenth axle to pass over it.
From that point on adhesion is the same regardless as the water has been pushed off the railhead or evaporated.

Given taht a normal shinkansen set has 64 axles.... this means it is not an issue.
Then again Japanese rail companies have experimented with air brakes for Shinkansen sets.

That pretty much endorses the use of distributed traction for modern passenger trains then!