Virtual coupling

[WatcherZero]

That's why you have anti-climber bars above the couplings.

 

[HSTEd]

This seems to be a solution to the problem of different coupling electrical standards and such.

When the answer used in American freight and on the Southern Region was to simply use as few standards as possible.
Hence the AAR standard that is still used today.

 

[cjmillsnun]

Replace something mechanically and electronically simple and completely failsafe, like a current coupling system, with something hugely electronically complicated and potentially open to all manner of defects, failures, unforseen behaviours, reliability issues and even malicious attack? There is not an acknowledged major problem with 'the old fashioned way' of doing it, so I see little justification for massively overcomplicating a very straightforward operation!

This. So much this. A mechanical coupling is cheap and proven. Yes you have to service it, but the idea of a physical link between vehicles in a formation in my mind is safer.

Lets see. Someone develops a way to jam the wireless link (not unfeasible). You now have effectively one vehicle under control and any number behind it not in control. It doesn't bear thinking about.

We have differing coupling standards and yes that's an issue. However this can be sorted out by a group standard that says all new trains have this type of mechanical coupling. Electrically they can be different, but if they can couple to each other mechanically, we can move trains around using units of different classes and this would avoid delays.

This virtual coupling IMO is a solution looking for a problem

 

[AngusH]

I don't know if this is a good idea or not.

However I think the interference issue is a red herring, assuming proper design.

At minimum this system must include some type of reliable, secure communication link between the separate vehicles.

"Reliable" in this case meaning a network link that guarantees that data is either delivered or a failure notice is generated.
Usually by exchanging extra acknowledgement information in both directions


Then on this reliable link, each vehicle must be sending regular sequential status messages to the other vehicles at standard time intervals.

If the link is disrupted by interference:
- the regular status updates between the vehicle will not be delivered when expected,
- the sender will know they weren't delivered
- whatever fail-safe procedure would occur on both vehicles.


So interference might bring everything to a stop, but it shouldn't cause a crash.


And yes, I would be willing to travel on such a train, if it passed the relevant approvals processes.

 

[jopsuk]

As some suggest, if it's a physical coupling with wireless control, that's quite well established- widely used on mega freight trains in the US for example.

 

[Phil.]

As some suggest, if it's a physical coupling with wireless control, that's quite well established- widely used on mega freight trains in the US for example.

I rather suspect that that is indeed what it is.

 

[cjmillsnun]

The first post makes it very clear there is no physical coupling.

Also any wireless link is by definition insecure either due to being intercepted and decided or more likely interference/jamming. A wired link is more reliable and secure.
--- old post above --- --- new post below ---

Another issue. All carriages would be none gangway. A guards nightmare.

GTR would want to replace their whole fleet with them then

 

[coppercapped]

The first post makes it very clear there is no physical coupling.

Also any wireless link is by definition insecure either due to being intercepted and decided or more likely interference/jamming. A wired link is more reliable and secure.

Simply making that statement in the second paragraph does not make it true.

There have only been some tests made so far to see if the principle works. The concept has been worked up by the German Aeronautical and Space Research Agency (DVLR) which also does work for the German train manufacturers. This is the German equivalent of the RAE Farnborough or of some parts of NASA. It is reputable.

You may be sure that if this concept comes gets as far as being used on the real railway all your concerns will have been addressed and the resulting technology will be at least as safe and reliable, if not more so, than existing couplers and wired connections. If trains don't have to carry half a tonne of couple at each end of a unit then the railways' green credentials will have been improved which seems to be a very important consideration for many of the posters on this forum.

 

[HSTEd]

Considering only two wires are required for EPS derived brake and train control systems to work, why would we ever consider physical coupling with wireless communications?
Seems to introduce another point of failure for no good reaosn.

 

[Dent]

Replace something mechanically and electronically simple and completely failsafe, like a current coupling system, with something hugely electronically complicated and potentially open to all manner of defects, failures, unforseen behaviours, reliability issues and even malicious attack? There is not an acknowledged major problem with 'the old fashioned way' of doing it, so I see little justification for massively overcomplicating a very straightforward operation!

The justification for virtual coupling is explained in the article. Current mechanical couplings do not support dynamically coupling and separating vehicles while they are moving, and it would be rather difficult to design mechanical couplings that did.

 

[BestWestern]

The justification for virtual coupling is explained in the article. Current mechanical couplings do not support dynamically coupling and separating vehicles while they are moving, and it would be rather difficult to design mechanical couplings that did.

The railway was using 'slip coaches' generations ago.

I see no reason a standard BSI coupler could not be modified to be perfectly capable of coupling or decoupling while on the move. Or any other autocoupler, for that matter.

 

[HSTEd]

In the era of very fast accelerating multiple units, the question then becomes why would you want to decouple or couple on the move?
It won't save very much time at all

 

[Johncleesefan]

In the era of very fast accelerating multiple units, the question then becomes why would you want to decouple or couple on the move?
It won't save very much time at all

How would uncoupling passenger trains on the move even work? You'd need a second driver in the rear to be formation to control it which would mean more expense and in the safety era we live in now this surely wouldn't be approved. Freight I can understand as in area it is still loose/hump shunted

 

[HSTEd]

How would uncoupling passenger trains on the move even work? You'd need a second driver in the rear to be formation to control it which would mean more expense and in the safety era we live in now this surely wouldn't be approved. Freight I can understand as in area it is still loose/hump shunted

Why would you need a driver?
The slip vehicle would go directly to a full brake application immediately upon release.

And modern trains don't seem to have different braking force for full service braking and emergency braking at most speeds.

Its not like a driver would be in any way able to stop the train hitting something.
The train would slow to a low speed and then proceed into the platform very slowly before making another application to come to a complete halt.

 

[Dent]

In the era of very fast accelerating multiple units, the question then becomes why would you want to decouple or couple on the move?
It won't save very much time at all

One usage case I can think of is services to be joined converging at a junction before a station. Currently this requires doing the coupling at the next station, and taking up two paths from the junction to the station.

You'd need a second driver in the rear to be formation to control it which would mean more expense and in the safety era we live in now this surely wouldn't be approved.

The second driver would still be needed if the services ran separately until a safe place to stop and couple them, so using dynamic coupling would not require any additional people.

What is "unsafe" about having a second driver on board a train but not driving it from the point the services join to the point where they can leave the train?
--- old post above --- --- new post below ---

The railway was using 'slip coaches' generations ago.

I see no reason a standard BSI coupler could not be modified to be perfectly capable of coupling or decoupling while on the move. Or any other autocoupler, for that matter.

Such a system could be developed, but it hasn't been. To develop it would involve development costs, and this team has evidently decided that these development costs would be better spent on developing virtual coupling.

If the traction and brakes are computer controlled anyway, virtual coupling only really requires a software update and very little hardware modification. In the days of ubiquitous computing, software solutions are often cheaper and more efficient that radically modifying hardware.

 

[Johncleesefan]

One usage case I can think of is services to be joined converging at a junction before a station. Currently this requires doing the coupling at the next station, and taking up two paths from the junction to the station.



The second driver would still be needed if the services ran separately until a safe place to stop and couple them, so using dynamic coupling would not require any additional people.

What is "unsafe" about having a second driver on board a train but not driving it from the point the services join to the point where they can leave the train?
--- old post above --- --- new post below ---


Such a system could be developed, but it hasn't been. To develop it would involve development costs, and this team has evidently decided that these development costs would be better spent on developing virtual coupling.

If the traction and brakes are computer controlled anyway, virtual coupling only really requires a software update and very little hardware modification. In the days of ubiquitous computing, software solutions are often cheaper and more efficient that radically modifying hardware.

Sorry I should of punctuated. No danger having two drivers to control. Danger uncoupling on the move with passengers on board. The system now doesn't need improving upon.

 

[HSTEd]

If every vehicle in the entire railway stock could interwork (like some sort of super Sprinterisation or super Southern Region) then the benefits of virtual coupling are reduced to saving paths in some very limited circumstances.

 

[Dent]

Danger uncoupling on the move with passengers on board.

What "danger"?

The system now doesn't need improving upon.

Virtual coupling offers advantages over the current system. It may not "need" to be improved upon, but doing so may well offer advantages.

Horse-drawn stagecoaches running on unmetalled road didn't need improving upon, does that mean that the entire rail system is pointless and should never have been developed?

 

[Johncleesefan]

Yes, that's exactly what I was getting to

 

[Ianno87]

One usage case I can think of is services to be joined converging at a junction before a station. Currently this requires doing the coupling at the next station, and taking up two paths from the junction to the station.



The second driver would still be needed if the services ran separately until a safe place to stop and couple them, so using dynamic coupling would not require any additional people.

What is "unsafe" about having a second driver on board a train but not driving it from the point the services join to the point where they can leave the train?
--- old post above --- --- new post below ---


Such a system could be developed, but it hasn't been. To develop it would involve development costs, and this team has evidently decided that these development costs would be better spent on developing virtual coupling.

If the traction and brakes are computer controlled anyway, virtual coupling only really requires a software update and very little hardware modification. In the days of ubiquitous computing, software solutions are often cheaper and more efficient that radically modifying hardware.

A down side of your diverging junction example would be how quickly it is feasible/safe to swing the points at a junction between the route of the front portion and the route of the second portion. The second portion would still require some amount of slowing down (or stopping) on the main line (i.e. Eating capacity) before the diverging route is set for the first train.

A good example would be Coastway-bound trains that currently split at Haywards Heath - split approaching Keymer Jn instead and your taking capacity away on the main line 'proper'