The station 'home signal' is so far out because it has to be spaced for the high through speed on the fast line. It is possible to have a signal closer in with a high through speed, sometimes known as a 'closing-up' signal, which allows a train to await clearance much nearer a platform and thus reoccupy more quickly. The problem with a closing-up arrangement is it usually introduces an odd aspect sequence with timed release of signals to rear or more than one single yellow. While that is allowed, it must be rigorously risk assessed as it can introduce some dangers of its own and the whole setup is clearly more complex and expensive. In older semaphore layouts such problems were less of a constraint as the only signal that was placed for braking distance was the distant relative to the first home, with the whole series of stop signals that it applied to placed more optimally nearer turnouts through a station yard. Block marker boards in ETCS allow a return to these principles to an extent as their placing is not constrained so much by braking distance. Even in a case like Peterborough where an overlay is proposed keeping the existing signals, additional intermediate blocks might be provided using marker boards to allow closing up, for fitted trains only of course. This idea was pioneered in the Thameslink core.
This. No context so a bit of a non-starter really.
I think there may be another possible factor here. Anyone who saw and read the whole thread about the previous incident, and had noticed there was a RAIB investigation intended, may have wondered if it was helpful to have the same discussion all over again?
Equally, might have been helpful to have that RAIB report released by now ...
You don't 'get the magnet for the points'. You receive an AWS warning for the signal at danger, irrelevant of the aspect received when it clears. The AWS system gives no indication to the driver of the route offered or the speed.
The Lumo incident was around 10:30 whilst the Grand Central incident was around 13:00. Would the sun have been in the same or similar position?
Apologies in advance if not talking about the same thing, but if running on green signals on the approach to Peterborough on the up fast then the AWS magnet that is associated with the 30mph points will be supressed. If you're approaching under any other circumstance (yellows or at danger) then it'll sound as the route wouldn't have necessarily been set from P468 and there's still a chance you may be routed across that set of points. In essence it is a magnet for the points. Makes logical sense when you've done it a few times. Similar setup for the down fast at Potters Bar for that 30mph set of points.
So you're saying you can approach Peterbro on the UF on greens and be routed straight across a 25/30mph junction without being checked down? With respect I find that hard to believe. The overspeed risk is huge give the 125mph approach speed. You would get checked down to P468 with an approach release or you can receive a flashing sequence for the move into P2.
I think they are saying that you can get checked down to P468 at Red and the AWS magnet for the 30mph speed restriction warning will still go off, even though the 30mph restriction is beyond the red. If the route is set in time you can get the flashing yellow sequence into both platform 1 and 2 - should really be approach release at red according to current standards. I wonder if these incidents will trigger a review of current non-compliant approach control arrangements on the network, I can think of a few.
Yes I take the point, and as you say the additional magnet is indeed for the 30mph move into P2. My point is that as soon as this warning is received and cancelled there is nothing else to remind the driver of the speed - P468 can and will clear with a junction indicator and it is purely down to the driver to have the necessary route knowledge and driving skills to ensure the correct speed is adhered to. I'm fairly sure the flashing sequence only applies to P2 as it is the higher speed option from P468 - as you said approach release is the safer method of signalling hence the flashing sequence is rarely (or never?) used. I've certainly never been give the flashers there.
The transition to ETCS L2 overlay makes it a little awkward, as that will essentially solve this problem. However it also limits the value of any work in the meantime. It depends what stage the signalling design was in when the Lumo incident occurred and how much change they are willing to make at this stage.
Nope. Greens only apply if routed towards P440. louis97's interpretation in post #43 is correct.
Indeed - all down to route knowledge, something never to be overlooked, even at locations you don't regularly stop at. The flashers will only be displayed if the route is set and proved before the train reaches the inhibit point (if the route is set and proved after the train reaches this point the signal will be approach released at red), so its possible whenever you have driven through there the route has never been set early enough or there has been a conflicting move.
It’s a Lumo train pictured at Newcastle.
Sorry - mistook it for Hull Paragon - corrected now.
AIUI on the Lumo, it didn't 'safely' negotiate the points - luggage was thrown from the racks and some passengers were injured when it fell.
Green
