West London Line power switch

[CheapAndNerdy]

Between Shepherd's Bush and Willesden Junction, the power supply changes over between overhead and third rail, along with the accompanying thumps and groans as the pantograph is being extended/retracted (a little startling the first time it is experienced). There is an overlap stretch of track that starts (I think) north of the A40 Westway. Is there a special line-side signal/sign that indicates where the changeover should happen or does it rely on driver knowledge to stop the train at an appropriate place? If the former, what does the sign look like?

Ta.

PS. Clapham Junction all the way round to Hampstead Heath - £1.30 on Oyster PAYG - well good value.

 

[Chris125]

If i remember correctly there's a sign like this. Of course a driver shouldnt need the sign ordinarily, but it serves as a useful reference point in bad weather for example.

Chris

 

[Tomnick]

Railsigns, ever useful, shows those signs on the North London Line proper, but different signs on the West London Line, as on this page.

 

[Peter Mugridge]

On one instance, on a late running northbound 377, I have experienced an "on the move" changeover ( albeit at very slow speed, but it certainly kept moving ).

 

[CheapAndNerdy]

Thanks guys. And now I've also found out that third rail is DC and overhead is AC (apart from Watford DC).

On one instance, on a late running northbound 377, I have experienced an "on the move" changeover ( albeit at very slow speed, but it certainly kept moving ).

Knowing (from a friend whose hubby is a signalman) how safety-concious the railways are these day, was that driver risking his job, even at such slow speeds?

 

[Mojo]

Thanks guys. And now I've also found out that third rail is DC and overhead is AC (apart from Watford DC).

The DC lines to Watford are third rail

 

[Railsigns]

DC electrification can also be overhead, such as the Tyne & Wear Metro (which includes Network Rail infrastructure between Pelaw and South Hylton) and various early systems that aren't around any more (e.g. Manchester-Sheffield-Wath).

 

[CheapAndNerdy]

The DC lines to Watford are third rail

:-x. I tricked myself into thinking it was all overhead north of London. Oh well, thanks for correcting me.

 

[Railsigns]

:-x. I tricked myself into thinking it was all overhead north of London. Oh well, thanks for correcting me.

There's DC third rail electrification in the Liverpool area as well.

 

[Trog]

The DC lines to Watford are third rail

BR style four rail to Harrow and Wealdstone. Then third rail plus disused fourth rail still used electrically for traction return from Harrow to Watford Junction.

 

[swt_passenger]

Knowing (from a friend whose hubby is a signalman) how safety-concious the railways are these day, was that driver risking his job, even at such slow speeds?

I don't believe it's a problem for drivers. The trains are designed to allow changeover on the move, but on the WLL the SN 377/2s don't normally need to do so because the working timetable includes a dwell time at the changeover section. I've been on a southbound train that changed while moving a couple of years ago.

Thameslink dual voltage 319s and 377/5s changeover during the station stop at Farringdon, as do North London Line 313s (changeover nowadays at Acton Central only) and FCC trains heading to/from Moorgate (changeover at Drayton Park). There is another AC/DC changeover point (which is not at a station) near Willesden Jn for trains running between the NLL and DC lines.

However Eurostar 373s always used to changeover when moving when they ran to Waterloo via CTRL1.

 

[142094]

The same used to occur on the Riverside branch here in Newcastle, when the electric locos used to use overheads in the tunnel and 3rd rail in the yards. I've seen a few pictures where the pan has been put up too high and hit the tunnel entrance. Shame not much of it exists now.

 

[O L Leigh]

The same used to occur on the Riverside branch here in Newcastle, when the electric locos used to use overheads in the tunnel and 3rd rail in the yards.

Other way around. The yards had overheads because of the risk to ground staff posed by the 3rd rail that was used everywhere else on the Tyneside electrification.

I don't believe it's a problem for drivers. The trains are designed to allow changeover on the move.

Not so. You can lower a pan on the move (switch from AC to DC) but you cannot raise one on the move. Attempting to do would risk damaging the pan and/or the OLE, and could even result in a dewirement. You must always stop first before attempting to raise a pan.

However Eurostar 373s always used to changeover when moving when they ran to Waterloo via CTRL1.

This is the only exception to the rule. Eurostars can raise a pan on the move because the design of the OLE and pantograph is different and was specifically intended to permit this type of operation.

O L Leigh

 

[142094]

Other way around. The yards had overheads because of the risk to ground staff posed by the 3rd rail that was used everywhere else on the Tyneside electrification.

Quite right, should have re-read what I was typing. I've found a few of the old electric poles at the former Trafalgar yard, surprising they haven't been removed after all these years.

 

[anonymous0101]

Other way around. The yards had overheads because of the risk to ground staff posed by the 3rd rail that was used everywhere else on the Tyneside electrification.



Not so. You can lower a pan on the move (switch from AC to DC) but you cannot raise one on the move. Attempting to do would risk damaging the pan and/or the OLE, and could even result in a dewirement. You must always stop first before attempting to raise a pan.



This is the only exception to the rule. Eurostars can raise a pan on the move because the design of the OLE and pantograph is different and was specifically intended to permit this type of operation.

O L Leigh

I also believe the Class 395s can do it on the move (according to one of the test drivers)

I believe the stopping point for the West London Line changeover is by a signal. Going south it says AC units Pan Down and the other way it says Pan Up but as you say the stopping points overlap and are not opposite each other.

But i'm not a driver so i'm not sure if i should be commenting.

 

[Failed Unit]

This is the only exception to the rule. Eurostars can raise a pan on the move because the design of the OLE and pantograph is different and was specifically intended to permit this type of operation.

O L Leigh

Not trying to be delibrately picky, but do the 91's have the same pantograph. I know it is slightly different to what is been discussed here but were the 91's not lower and raising thier pans on the move during the Hitchin works recently when they coasted through the problem area. I have a feeling the 365's were also coasting but not so sure about that myself as FCC were often suspended during the works.

 

[O L Leigh]

Cl91's don't have the same pan as Eurostars, and the OLE on the ECML is far from robust.

As for the coasting at Hitchin, this is a new rule that had been trialled by GNER and is now rolled out across the network. The rule is quite long and involved but, right at the end, it says that "Unless otherwise shown in your train operating company instructions, you must stop your train to raise the pantographs when you are sure all the pantographs have passed the affected area". Now it may be that East Coast have different operating instructions (though with the state of their overheads I frankly doubt it), but I was very clearly told during my training that I must never attempt to raise a pan on the move and must always stop first.

O L Leigh

 

[Failed Unit]

Cl91's don't have the same pan as Eurostars, and the OLE on the ECML is far from robust.

As for the coasting at Hitchin, this is a new rule that had been trialled by GNER and is now rolled out across the network. The rule is quite long and involved but, right at the end, it says that "Unless otherwise shown in your train operating company instructions, you must stop your train to raise the pantographs when you are sure all the pantographs have passed the affected area". Now it may be that East Coast have different operating instructions (though with the state of their overheads I frankly doubt it), but I was very clearly told during my training that I must never attempt to raise a pan on the move and must always stop first.

O L Leigh

I doubt East Coast have different instructions, the Hitchin works are the only place I have known this happen which as you state is a special event. You are right considering the state of the ECML wires you wouldn't want to risk it. I know the pan can be dropped quickly if a problem occurs, but I have also got a feeling that should this be needed the overhead will probably be coming with the pantograph anyway!

 

[O L Leigh]

Apparently we had a brief episode of coasting with the pan down as a consequence of a lineside fire damaging the OLE, but I was off that day so missed it. I expect it's happened elsewhere at other times too but it's not something that gets heard about.

Having seen how long it takes between pressing Pan Down and the pan breaking contact with the wire, I've always been conscious that such action would probably be too late to avoid any obstruction on the overheads. What it must be like for those poor souls at East Coast tanking along at 125mph doesn't bear considering. By the time you've spotted something ahead, worked out what it is and which line it's over, there would be almost no time left to react.

But anyway, I fear the topic is starting to drift.

O L Leigh

 

[Old Timer]

As OL Leigh states, Continental OHL equipment is designed differently to ours and is tensioned to a higher degree, thus allowing the pan to be lifted into it, without causing the OHL to undulate.

Lifting a pan into UK Equipment at speed is a more complicated issue and will be affected by both the gradient of the OHL contact wire at that point as well as the tension. There is also the issue that an arc will be drawn as the pan comes into contact with the wire, and if there is any pan bounce then more than one arc will be drawn as the pan breaks and remakes contact. This is not good when stainless steel droppers are installed.

 

[Trog]

Could you raise the pan with the traction motors switched off. So no current would be drawn while the pan was establishing contact with the knitting? Only starting to draw power once the pan was up and firmly in contact with the contact wire.

 

[455driver]

Could you raise the pan with the traction motors switched off. So no current would be drawn while the pan was establishing contact with the knitting? Only starting to draw power once the pan was up and firmly in contact with the contact wire.

You wouldn't be taking power when raising the pan, the arc would be drawn because the electricity is used for many other pieces of equipment, compressors, air con, lighting etc. If you add it all up it is quite a current draw!

 

[O L Leigh]

No. You hold the button in for a count of 15 seconds as you would do anyway when raising the pan when stationary. This raises the pan but keeps the VCB open until the button is released, so there is only a minimal current draw.

But it still doesn't get around the problem of a bouncing pan and what it does to the tensioning and gradient of the contact wire. Drawing an arc is one way of damaging the equipment, but you can still drag the whole lot down without one. Setting up a sudden and violent undulation would be just enough to shake some of the droppers free.

O L Leigh

 

[captainbigun]

No. You hold the button in for a count of 15 seconds as you would do anyway when raising the pan when stationary. This raises the pan but keeps the VCB open until the button is released, so there is only a minimal current draw.O L Leigh

Easier in a loco as you can tell when the pan has hit the wire! You'd be surprised at the number of drivers I've encountered who close the BIS walk to a cab, press and release pan up and then wonder why the pan is slow to raise or fails altogether. Really bad practice on Classes 81-87 as an arc will be drawn because the breaker is closed upon release of the pan up button. Class 89 checks for line volts once the breaker is closed and if no volts are seen opens the breaker. Not sure about 90/91 or 92 for that matter.

The BW high speed and sons of are more friendly on raising and lowering. SF's can be a little savage on both fronts as they rely on a large spring not a raise/lower cylinder as with a BW.
--- old post above --- --- new post below ---

Cl91's don't have the same pan as Eurostars, and the OLE on the ECML is far from robust.

The second pan is a standard BW high speed, this is the pan used for the DC collection but it can be used for AC should the main (Faiveley) pan fail. The pan fitted to Class 91 is a BW high speed but it sits on a narrower frame than the more common derivative found on most units and other locos.

 

[O L Leigh]

Easier in a loco as you can tell when the pan has hit the wire!

Perhaps. Then again, the pan on a single EMU is going to be no more than two coaches away. If you keep the cab window open you can still hear the "bzzt" as the pan makes contact with the wire.

Class 89 checks for line volts once the breaker is closed and if no volts are seen opens the breaker.

Presumably at that point you'd have to wonder why the breaker light is still on, poke your head out the window to check that the pan has gone up and then press Pan Up/Reset to get the VCB closed and the loco powered up.

The BW high speed and sons of are more friendly on raising and lowering. SF's can be a little savage on both fronts as they rely on a large spring not a raise/lower cylinder as with a BW.

Oh absolutely. They are also much less prone to bounce than a Stone Faiveley "bicycle frame" pan and arc less as a consequence.

However, the Brecknell Willis HSP is still very fragile and more prone to breaking as a consequence. In fact, on one occasion a colleague of mine broke one coming into Liv St. He was just rolling in at 15mph when his passengers reported a loud bang which turned out to be the pan falling between the coaches. As the driver of the next train out, I was asked to inspect the OLE to see if there had been any damage to the wires or any reason for the pan to break. I found absolutely nothing wrong and trains continued to run in and out of the station without any further incident.

The second pan is a standard BW high speed, this is the pan used for the DC collection but it can be used for AC should the main (Faiveley) pan fail. The pan fitted to Class 91 is a BW high speed but it sits on a narrower frame than the more common derivative found on most units and other locos.

Again, absolutely. However, as Old Timer has already pointed out, Continental Europe has a better standard of OLE than the UK and has been designed specifically to permit pans to be raised on the move. Trying that here in good old Blighty is a whole lot more risky.

O L Leigh

 

[hello]

in the early 90's it was standard practice to raise pan as you were running into farringdon with 319's, i would say it was around 1994 when it stopped being normal practice, and it was because it started becoming common that the doors would not release, so pan would we put up after doors had been closed. there was also the odd occasion when you might lose a pan, especially if you had 8 on

 

[charlesn132]

I don't believe it's a problem for drivers. The trains are designed to allow changeover on the move, but on the WLL the SN 377/2s don't normally need to do so because the working timetable includes a dwell time at the changeover section. I've been on a southbound train that changed while moving a couple of years ago.

Thameslink dual voltage 319s and 377/5s changeover during the station stop at Farringdon, as do North London Line 313s (changeover nowadays at Acton Central only) and FCC trains heading to/from Moorgate (changeover at Drayton Park). There is another AC/DC changeover point (which is not at a station) near Willesden Jn for trains running between the NLL and DC lines.

However Eurostar 373s always used to changeover when moving when they ran to Waterloo via CTRL1.

There are no more 313s on the North London Line, only 378s

 

[traji00]

Back on topic, I asked myself a while ago: "At what extra cost would it be to extend the OHLE to Shepherd's Bush?" so that,
a) AC/DC changeovers could be carried out while stationary, &
b) Time could be saved as trains wouldn't need to stop/slow down

 

[swt_passenger]

Back on topic, I asked myself a while ago: "At what extra cost would it be to extend the OHLE to Shepherd's Bush?" so that,
a) AC/DC changeovers could be carried out while stationary, &
b) Time could be saved as trains wouldn't need to stop/slow down

The cost for NR at the moment would have to include AC immunisation of the LU H&C signalling where it crosses the WLL.

IIRC it has been looked at but won't be done until after LU have resignalled in the area.

From the Cross London RUS:

Description

Move the AC/DC changeover on the WLL to Shepherds Bush station.

Issue

The AC/DC changeover on the West London Line is currently located close to
North Pole depot. This requires all electric services to stop in section to effect the
changeover, costing around two minutes per train. The opportunity therefore exists
to look at moving the changeover point to the station at Shepherds Bush.

Recommendation

The cost of the alteration would be prohibitive, due to the need for extensive
immunisation of the signalling equipment on the surrounding routes, including the lines
operated by London Underground. However, it is understood that the Hammersmith
& City line is due to be re-signalled in 2013, and this may give the opportunity for the
issue to be revisited.
An alternative solution would be for the changeover to be undertaken on the move, and
it is recommended that this is progressed during the procurement process for any new
electric rolling stock required for the route.

 

[class313]

I was wondering if anyone could help me, when I was on a 378 at North Pole Junction where it raised its Pantograph a little while ago, the doors released when the pan went up, the driver clearly did not know, because you could hear him trying to apply power, but the brakes were still on, because the doors were open. I have also noticed at Acton Central when the 378's put their pan up there, they often roll back a few yards. I am not sure if this as a fault with the 378 equipment when switching over, but it is quite odd.