Unusual moves and rostering drivers to them.

If there were three people in the cab, then it's probably the driver, an instructor operator and a trainee.

Two trains reverse east to west on a Sunday morning. The IO and trainee join the train at Northfields or Acton Town and with the rostered driver, work it up to Kings Cross and reverse east and west. The IO and trainee leave the train at Russell Square westbound and pick up the second KX reverser on the east. This way the trainee gets two trips over the reversing point.

It depends. Some moves are naturally easier than others.

The consequences of a mistake can vary. Stop in the wrong place and change ends and it will cause a delay. Miss a signal you didn't know was there and that's a SPAD. Likewise if you don't know the speed then you could go too fast and potentially cause a derailment.

What about if there's an unexpected failure and the simple move you thought you were doing then turns into something more complex? Again greater potential for delays, and more importantly for mistakes to occur.

The above list is by no means exhaustive. A certain amount of common sense applies, for example a driver might be happy doing an unfamiliar basic move after a quick refresh of their Line Knowledge Book. But for a more complex move, like going into a depot, this is not sufficient in my view.

Generally speaking, a driver should never be in the position where they're doing something they're not comfortable with.

Are the limi of shunt moves on the Central not controlled by ATP to prevent a T Op from going too far?

I have to ask:

What exactly is a 'limit of shunt'.

I'd always assumed, from context (and the literal meaning of the words) that it was something that told drivers how far they could reverse without interfering with some other section of track.

But that does not seem to be the case in some of the instances mentioned here.

I think the simplest way to ask the question is: What it an LOS intended to prevent?

So an 'LOS' is something that can only be used when either:

1) All trains are the same length,

or

2) The LOS is positioned for the shortest train,

or

3) There are multiple LOS indications each applicable to a certain train length?

Forgive my slowness, here, but one of the reasons I had problems inferring the meaning was that I'd always assumed that 'shunting', was something that would necessarily happen on areas of track not controlled by track circuits. (Hence my assumption that it was some sort of reversing limit to stop a train backing onto an area that was controlled by track circuits.)

This is true, but it's common to have stopping marks for each train. So, on the SSR these days, there are lots of S7 stopping diamonds positioned shortly before the actual limit of shunt. The limit of shunt really is the limit, no train that's shunting should proceed past that and it's also the stopping mark for whichever happens to be the longest train. But then you get stopping marks for the shorter trains as well positioned slightly before.

On the mainline they use limit of shunt markers where LUL have fixed red lights. So, taking a very simple example, at Streatham Hill there's a limit of shunt board at the country end of the up platform for down direction moves from the up sidings and mainline. But, to my knowledge, LUL always use fixed red lights for such moves. It's also very common on the mainline to have their limit of shunt signals, which are plated LOS but consist of a position light shunt signal with only the two reds on the bottom permanently lit. They can't clear. These are often used for facing shunt moves. So like at Marylebone, you can proceed out of the station in the down direction along the up main line until the limit of shunt for a shunt back into an alternate platform at Marylebone. There aren't many equivalent locations on LU, but I'm sure you'd have a proper fixed red here all linked up with trainstops or ATP.

But where LUL has limit of shunt boards, they are always for right direction moves to my knowledge. So, at Liverpool Street, the LOS is for a mainline shunt over the trailing crossover. So you're gonna head west out of the westbound, stop at the limit of shunt, change ends, and head into the eastbound platform. So the approach to the limit of shunt is right direction. The move, say, from Liverpool Street sidings into the eastbound platform is wrong road and will have a proper fixed red all linked into the signalling. Passing that would be a SPAD. But passing the limit of shunt on the westbound main wouldn't be. The train will be cleared out of Liverpool Street westbound along the westbound main and it'll be cleared up to the next occupied block or signal being held at danger.

I think if there'd been engineering plant on the line, obviously you'd've had to have a proper possession, with all the red lights associated with that. Now passing them without authority is a SPAD. And, again, if there'd been any other trains on the line in blocks ahead, yeah, that'll be picked up by the signalling and the ATP will give you a target speed of 0 for the occupied block and if you enter that block without authority, that's a SPAD.

ATP complicates things a bit, but take traditional signalling. Let's take Dagenham East. So for the mainline shunt move here, FG4 will clear for the mainline shunt move, but it will clear with a straight green - main aspect - and it clears you to A956 - which may or may not be clear, but whatever. The signalling permits you all the way up to A956. That's safe. Pass FG4 at green and there's no SPAD. Now it's up to you to stop at the limit of shunt if you're supposed to shunt back. If you pass the limit of shunt, you've not SPADed, you've not entered an occupied block, there's nothing up ahead for you to hit. But getting you back to FG18 may be a bit of a headache. Now, if for some reason there is a train in rear of A956, or FG4 has failed or something like that and you're given authority to pass signal FG4 at danger and proceed to the limit of shunt only and you carry on past the limit of shunt - that is an issue.

Now it's a different matter at somewhere like Upney. If you're cleared wrong road by the shunt signal into the westbound platform and you pass the FRL at the end of the westbound platform (which could be thought of as a bit like a limit of shunt) then that is a SPAD.

I know of one possible exception to this. So at Harrow-on-the-Hill, JB3, the station starter at platform 1, is the main signal clearing you to JB7 on the northbound main. Beneath JB3 is shunt signal JB92 for the mainline shunt from the northbound main. I would guess that JB92 clears you as far as the limit of shunt only. So the situation at Harrow-on-the-Hill may be a bit different.

This is much more common on the mainline, where it's often possible to set a subsidiary route for a main line shunt move, which I believe clears you only as far as a limit of shunt. I believe these subsidiary routes still require the whole block to be clear, but they have reduced overlaps. But of course you're proceeding here on a clear shunt signal, not a main aspect. So at somewhere like Liverpool Street, or Dagenham East, it's main aspect only on the station starter.

They're normally placed for the longest passenger train. In past times numbered boards were used where different length trains ran, most commonly 4, 7 or 8 depending on the line. Some of these still remain in situ. Such boards were also used in reversing sidings, and in some platforms as stopping marks at places where the diamond was not used.

For engineers trains a reversing berth depends on where signals are placed, generally I wouldn't expect an engineers train to use LOS boards as their primary means of stopping. A short train might need to make sure it draws up to the board to release any route holding apparatus though.

My bad. I guess I'm just used to mainline style and EKT in particular. I hadn't realised that an LU Limit of Shunt is encountered when running under main aspect signals, I was envisaging the NR scenario outlined above by tut.

I would say Rayners Lane WB platform, reversing onto EB tracks is a very uncommon move. I recollect being a passenger on that day and seeing lots of people going down onto the platform, expecting to go to Uxbridge and being very confused indeed!

How common is terminating eastbound Jubilee line trains in the westbound platform at Canary Wharf?