Edwin_m

That's probably true in theory, but having spent a significant part of my life running hazard workshops for Metrolink I think I can safely say it's not true in practice. Blue "you must do this" signs are pretty rare, one way being the only common one, and the blue "you must be a tram" sign really isn't obvious and is easily confused with the blue signs showing trams that are provided at pedestrian tramway crossings. Tramways elsewhere tend to provide "no entry" bollards between the tracks or other measures to provide a physical deterrent, although that's more difficult if buses need to use it too. However, I do agree an enforcement camera would probably work wonders here.

That's absolutely asking for other vehicles to use the tramway. I suspect 90% of drivers don't understand the blue "tram only" (tram and bus in this case) sign and most other tramways have moved to a no entry sign with "Except Trams" plate. There's also no other indication of other traffic diverting except a dotted line and arrow that could easily be missed, especially if driving close behind a tram. Fortunately this diveunder has a full road surface to accommodate the buses, so cars won't get trapped like they commonly do in Nottingham and Manchester despite those having various extra deterrents fitted. From safety discussions on Metrolink, there at least the approach is to provide cyclists with a reasonable signed alternative, but not worry too much if they don't choose to use it. This provides a defence against those sorts of claims.

They bring it home, but they don't necessarily eat it. Sometimes it would be better if they did.

And I think EWR put the track down when they're finished.

Where boxes A and B were so close that A could only clear its distant if B had also done so, this was often achieved not by a mechanical slot or some electric arrangement, but by the signalman at A observing B's distant directly if visible, or an indicator in box A. This always struck me as a major loophole in the system, and was contributory to the collision of a Pullman at Knowle & Dorridge in 1963. https://www.railwaysarchive.co.uk/docsummary.php?docID=513

Probably an example of what was described earlier, where there is a stopping and a non-stop control. If the approaching train is stopping the signaller pushes a button which keeps the signal at red and the crossing open to road traffic (assuming no train the other way). When ready to depart, the crossing sequence is started but the signal doesn't clear until the barriers are down.

Good description. Interesting that the OP's photo shows a tractor pulling a trailer of hay bales, which might well qualify as a large or slow vehicle. Did they stop before crossing? If so then I think the signaller would have put the signal to danger before allowing them to proceed. However, looking on Streetview I can't see a "large or slow vehicles" sign on either approach to the crossing, though there is a caravan site just adjacent which might suggest such vehicles are quite frequent here.

Before they decided on Mornington Crescent, wouldn't they have to propose the plaque at 20 or so other stations?

While they have been a threat in the past, the threat uppermost in people's minds would have been the bombings on Madrid suburban trains in 2004. I've not used a Spanish high speed service but passed through Atocha many times, most recently in 2018, when there were security checks on the HSR platforms but they seemed pretty desultory. Any intending terrorist could probably cause more carnage by letting off a device in the security queue instead.

I believe this is related to the hazard of a train stalling in the tunnel out of Queen Street and the driver being unaware it is rolling back - something that's happened at least once with serious consequences and also gave rise to the incoming locomotive staying attached to assist an outbound loco-hauled train out to Cowlairs. In that situation the last vehicle would emerge from the tunnel first, so a member of staff in that vehicle had more time to apply the brakes before it reached the buffer stops. So if such a formation ever got to Queen Street, loco haulage of a DMU formation with no brake or cab in the last vehicle wouldn't address the hazard. Tail traffic would only be allowed if it had a brake compartment with the guard riding in it. Note also that a cabbed DMU vehicle at the rear would be OK even if the cab was facing forwards.

Surely out of Bradford? There was another DMU buffer stop collision on the Royton branch just north of Oldham, and DMUs must also have used the Werneth Incline (1 in 27) between their introduction locally in 1958 (per Disused Stations) and closure in 1962 (per Wikipedia).

Not sure I buy that in respect of Chesham, considering the LibDems are probably more pro-rail than the Tories. I think their candidate truthfully but diplomatically said words to the effect that the decision was made and there was no point in trying to stop it now.

If it followed the busway then it would need a very slow all-stations service (and the extra stations for it to stop at), otherwise the people who use the buses now would end up back in cars on the busy A14. The railway is more suitable for larger but more separated clusters of development, allowing the same trains to serve a limited number of stations and still provide fast enough times to be competitive for inter-urban travel as well as commuting.

I think the other factor was that GWR had some surplus 387s and depot capacity to service them, that could be converted for the Hex service (though judging by a recent ride, still much more of a standard train than the 332). The fleet was presumably sized to cover the cancelled electrification to Oxford.

That's consistent with my recollection. I'm not sure if the replacement of the 332s was solely due to the ATP/ERTMS incompatiblity, as it also avoided having to build a new depot for them so HS2 could take over the existing site for the OOC station. To be fair, ERTMS is an open architecture with reasonable assurance of equipment continuing to be available. Any other ATP system would have tied us to a single supplier who probably wasn't interested in providing non-standard kit into the future - as was the case with the two BR systems. Network Rail and its predecessors have sometimes suffered from the opposite of "not made here" when procuring signalling systems. Consider the Ansaldo and Siemens (before the takeover of Westinghouse) systems fitted at Stockport and Bournemouth which were never finished and used huge amounts of cabling respectively, and the Bombardier one at Horsham (I think) that was never even commissioned.

The reason was that trains on the Heathrow branch were required to be fitted with GW-ATP. Just running there under TPWS was considered insufficiently safe, and I don't think the trackside equipment was fitted anyway. So Crossrail units would have needed GW-ATP as well as the other systems. ETCS was considered to offer equivalent levels of safety, so replaced the GW-ATP on the branch. At the same time the 332 units were replaced by modern 387s which were already prepared for ETCS operation.

This was recognised as an issue with the BR ATP systems back in the 90s. In some places "infill loops" were provided to act as a continuous balise. There was also a "release speed" which drivers could accelerate to if they could see the signal had cleared, but if was still red the system would still be able to stop the train, beyond the signal but within the overlap so not at risk of collision. With continuous transmission, ETCS Level 2 avoids this issue completely.

I'd guess that it's because the haul roads are slow speed and they want to do the minimum of earthworks for them (to reduce time, cost and impact). So they may have to zigzag to get a reasonable gradient over even minor undulations in the terrain.

Reminds me of the Simpsons episode where the family car is T-boned and pushed along in front of an Amtrak train, and Homer climbs out to get some food from the lounge car.

The selfie stick question relates to the clearance to platforms. For clearance to bridges which is the issue here, as far as I can see there's no hazard to people if it's too tight, just a risk of arcing which may cause some wire degradation and a power outage that can immediately be reset.

Usual practice would be to provide electrification clearances where practicable, but not to re-build structures if the only reason to do so would be to provide those clearances. Are there any arched bridges that are being left largely alone, with both tracks continuing to pass through the same arch? If so these are likely to need work as part of any future wiring (unless electrification cost saving initiatives find ways to avoid this in the meantime).

Moorgate and the ECML will be Level 2, which is already running on Thameslink. It produces some capacity benefit from being able to optimise block sections without the constraint of lineside signals, and the absence of those signals also reduces costs somewhat. But it remains fixed block with lineside train detection equipment. Moving block under ETCS doesn't happen until Level 3, which isn't in service anywhere.

Arguably all signalling is digital, as it works with binary states (signal off or on, point normal or reverse). A mechanical interlocking does the same job as a digital logic controller, just using a different technology.

Not sure this timeline could have worked. The ECML was finished in 1991, by which time all the Regional Railways Sprinter fleets had been ordered and most of them delivered. The timescale for TPE would probably have been similar to the 7 years from approval to completion of the ECML, meaning that the only possible saving would be to soldier on with DMUs for longer on Thames and Chiltern and replace them with cascaded Sprinters instead of building the Turbos.

Reminds me of a cat called Moses we had when I was a child. My mother decided he didn't get enough exercise and he was put in the car and dropped off half a mile away to find his way home. General consternation when he wasn't seen for some hours, until we realised he'd managed to sneak in unnoticed and take up his usual position on top of the boiler.