One of the things drivers always forget to do!

[Julian G]

Did that ever happpen to anybody?
There is a sign that mentions outside Farringdon
"AC TRACTION MUST NOT PASS THIS POINT"
Maybe they should put signs Put Panto down if for City TL
BUT there is a sign on DOO Boards saying "CHECK SIGNAL ASPECT"

Interesting thing happened on my commute from Bedford to Moorgate this
morning.

Train pulls into Farringdon as normal but driver forgets where he is
going (doh!) and lowers the pantograph (I am assuming it wasn't
uncommanded although that could be a possibility). I know the panto
came down while stationary at Farringdon because I was sat right
underneath and heard it drop.

So off we jolly well go, only to get about 100 yards round the bend
towards Barbican and, you've guessed it, everything cuts out. Complete
silence.

So we're now without power with the back of the train straddling the
junction. From where I was sat it looked like nothing was able to get
in or out of Farringdon.

Whoops!

Result one embarrased train driver (now outside his train staring up
into the empty space where the pantograph should be) and wondering how
to get us moving again.

A bit of ***fing about in the cupboard under the panto and fifteen
minutes later we were on the move to a muttered apology about
'overhead power problems'.

I was aware that this was possible but in three years of commuting
this is the first time that I have actually seen it happen. I wonder,
does this occur often?

Makes me wonder what would happen in the opposite scenario - if the
driver kept the panto up and moved off from Farringdon in the
direction of City Thameslink
KDW

Pantographs have been damaged when drivers have forgotten to lower
them before departing Farringdon southbound on DC traction. Next time
you are travelling into Moorgate, take a look at the tunnel mouth on
the line to City Thameslink. There is a beam high over the 'four
foot' to knock down any raised pantographs. I do not know how
effective it is but believe its installation was reactive.

Regards

Barry

 

[O L Leigh]

Interesting.

I'm not familiar with the area so I don't know the layout, plus it's not entirely clear exactly what is supposed to have happened. Are you saying that the driver dropped the pan when it was still required to run in AC mode, or something else?

A dropped pan can easily be raised provided that there is sufficient air to operate the air motor and close the VCB. If he'd only just run off the juice there should have been plenty of that, meaning that he just needed to press the button and away he'd have gone. It sounds more like he had a pan problem in the station that he may have been unaware of.

Running off the wire with the pan up is a more serious issue. Most units have a system whereby certain damage to the pan or the pan going overheight will automatically drop it by blowing out the air holding it up. Without this, a pan going overheight will break it's back and that will be the end of that.

The use of a beam to "knock down any raised pantographs" sounds pretty barbaric and will probably result in a broken pan. The GN line into Moorgate from Drayton Park has a much simpler and more graceful system. Quite simply, there is a section of dead wire that runs into the tunnel. Should any driver attempt to enter the tunnel with the pans up will find he loses line volts and won't be able to proceed very far, as Cl313's can't draw power from the juice rail with the pan raised. It should then become obvious to him/her what has happened, and corrective action can be taken without causing any damage to the train.

one TN

 

[Tom C]

There has been numerous incidents at Farringdon Junction involving trains entering Snow Hill Tunnel (where the wires end) with pants up and hitting the entrance to Snow Hill. As for Moorgate, as TN said, if the train came off the 3rd rail with pants down there should be enough power to stop and actually raise the pantograph and carry on although perhaps this was a faulty unit??

There WAS a pantograph from a 319 dumped in Smithfields Sidings (adjacent to Farringdon) where another victim lost its head.

Southern used run 319's without pantographs and at least two Thameslink joined that fleet after a arguement with Snow Hill.

 

[HR2]

never knew why they had to juice up the tunnels north of Farringdon with OHLE anyway? They could have continued with 3rd rail until it pops above ground near St Panco

 

[ChrisCooper]

It's because the line was electrified using 25kV overhead in the late 70s, and at that time trains only ran to Moorgate, and the service was operated by 25kV only 317s. It wasn't until the early 90's when Thameslink started that trains began switching to 750v third rail at Farringdon and running through onto the SR. AFAIK, the reason for Farringdon as the changeover, rarther than further south, was that there is restricted clearance in the tunnels, and also it is at the boundry between the MR and the SR, and also the point where control passes from West Hampstead to Victoria South pannel. Also, it's desirable to have the change over at a station, since it saves time as it can be carried out at the same time as station duties, wheras having to stop north of Kings Cross Tunnel would be a waste of time (313s, 319s and 377/3s must stop before changing from overhead to third rail or vice versa).

 

[Julian G]

It's because the line was electrified using 25kV overhead in the late 70s, and at that time trains only ran to Moorgate, and the service was operated by 25kV only 317s. It wasn't until the early 90's when Thameslink started that trains began switching to 750v third rail at Farringdon and running through onto the SR. AFAIK, the reason for Farringdon as the changeover, rarther than further south, was that there is restricted clearance in the tunnels, and also it is at the boundry between the MR and the SR, and also the point where control passes from West Hampstead to Victoria South pannel. Also, it's desirable to have the change over at a station, since it saves time as it can be carried out at the same time as station duties, wheras having to stop north of Kings Cross Tunnel would be a waste of time (313s, 319s and 377/3s must stop before changing from overhead to third rail or vice versa).

Excuse me, I think you mean Cl377/2 not 377/3

 

[O L Leigh]

There has been numerous incidents at Farringdon Junction involving trains entering Snow Hill Tunnel (where the wires end) with pants up and hitting the entrance to Snow Hill.

There WAS a pantograph from a 319 dumped in Smithfields Sidings (adjacent to Farringdon) where another victim lost its head.

Hi Tom,

Is there a gap between the end of the knitting and Snow Hill Tunnel, or do the wires just stop at the portal?

I still think that the best option would be to de-energise the wiring immediately at the end of Farringdon platform as a safeguard to prevent trains getting as far as the tunnel with the pans still up, as happens at Drayton Park. Otherwise, stop the knitting short of the tunnel portal so that at least the pan has a chance to go over-height to trip the ADD (Cl319's do have ADD, don't they...?) and drop onto the roof before there's any chance of it smacking the brickwork. Electrifying up to the tunnel portal with live OLE is just asking for trouble.

313s, 319s and 377/3s must stop before changing from overhead to third rail or vice versa.

Hi Chris,

Not sure about traction changeovers, but generally speaking you can drop a pan on the move. It's actually vital to do this if there's an obstruction on the OLE that could snag the pan and you can't stop in time. However, you must never attempt to raise a pan on the move as you may pull the lot down. The only exception to this that I'm aware of are Eurostars which have more sophisticated pans and better OLE to run off.

one TN

 

[Julian G]

Hi Tom,

Is there a gap between the end of the knitting and Snow Hill Tunnel, or do the wires just stop at the portal?

I still think that the best option would be to de-energise the wiring immediately at the end of Farringdon platform as a safeguard to prevent trains getting as far as the tunnel with the pans still up, as happens at Drayton Park. Otherwise, stop the knitting short of the tunnel portal so that at least the pan has a chance to go over-height to trip the ADD (Cl319's do have ADD, don't they...?) and drop onto the roof before there's any chance of it smacking the brickwork. Electrifying up to the tunnel portal with live OLE is just asking for trouble.



Hi Chris,

Not sure about traction changeovers, but generally speaking you can drop a pan on the move. It's actually vital to do this if there's an obstruction on the OLE that could snag the pan and you can't stop in time. However, you must never attempt to raise a pan on the move as you may pull the lot down. The only exception to this that I'm aware of are Eurostars which have more sophisticated pans and better OLE to run off.

one TN

by the way, everytime I travel on the OSX to Liverpool St (Under the Pantograph!)
As It approaches the Junction where the SX line joins the Chingford, the buzzing cuts off, and then starts again, Is that a neutral section?
----------------------
But Look why the 319s had to be different from the others

However doors in the cab fronts were still required to enable evacuation of the units in the Metropolitan Widened Lines tunnels between Farringdon and Kings Cross.
These units were fitted with retention tank toilets, also because of the tunnels.
In their early days the 319 units experienced an number accidents with their pantographs striking overhead structures whilst incorrectly raised on the Southern. This was found to be due to a wiring design fault - operating the overload reset whilst working in the 750v dc mode also disastrously raised the pantograph unless dc traction mode was first re-selected. Unit utilisation allowed use on internal workings both north and south of the Thames, but such workings increased on the Southern following a major revision of the Thameslink timetable cutting back on the number of destinations served south of the Thames.

 

[O L Leigh]

by the way, everytime I travel on the OSX to Liverpool St (Under the Pantograph!)
As It approaches the Junction where the SX line joins the Chingford, the buzzing cuts off, and then starts again, Is that a neutral section?

OSX...?

There is a neutral section on the chord between Coppermill Junction and Clapton Junction (where trains from Tottenham Hale join the Chingford line towards Hackney Downs), which would explain the temporary halt in the buzzing (among other things).

one TN

 

[Julian G]

OSX...?

There is a neutral section on the chord between Coppermill Junction and Clapton Junction (where trains from Tottenham Hale join the Chingford line towards Hackney Downs), which would explain the temporary halt in the buzzing (among other things).

one TN

One Stansted Express