david.hill64

Unlikely and it wouldn’t be sensible to abandon an integrated set of standards too quickly. The short term exception in my view would be the electrification clearances in the Energy TSI. Reverting to the proven safe BR standard would knock hundreds of millions off the cost of electrification.

The rolling stock TSI (technical standard for interoperability) requires a standard of headlights but not yellow ends. As the TSI is mandated by EU law it supersedes national standards. EU countries are not permitted to deviate without a derogation from the European Commission. RSSB in its guidance note states that there must be a risk assessment if yellow is not used as an additional safety measure, but cannot force the issue.

Good heavens Ken! How many minutes did that one take?

I think that New York has installed external voltage regulators before the UPS systems to protect against over-voltages, which were becoming more common. When we installed signalling systems in Thailand, India, Pakistan etc we would always ensure that the power supplies were capable of dealing with the relatively unstable incoming power. I guess UK is heading that way.

Don't get shirty! I did read the article, which I though was constructive and informative. Clearly all of the available power supplies had the same problem, which isn't surprising if they are all from the grid. My point is that if we can no longer rely on stable power supplies within the correct specification, then the industry will have to spend money to compensate for the deficiencies of our new generation system. Yes the system shut itself down to protect itself, but it would be more sensible for the protection to be upstream of the conditioning/UPS/secondary source so that the UPS kicks in when the power is out of spec. It may not have been necessary before but recent events are likely to be the precursors of the future so thinking will have to change. Working in countries where mains power supply isn't as good as that which we (used to) have means that the protection on essential circuits is arguably better than we have. If you had read my comment properly instead of getting in a huff I think you would have understood that I was getting at the grid not at NR.

All very sensible, so I wonder why an over-voltage can bring down a whole area? Presumably this protection wasn’t yet fitted.

Interesting. As we rely more and more on intermittent sources for power generation, I wonder of we will need to change the thinking behind powering signalling systems on the mainline. In every metro signalling installation I have been involved with all signalling supplies are conditioned by a UPS system, usually fed from two independent sources and a diesel generator in addition to the battery back-up. A voltage spike wouldn't crash the system.

Brilliant! Thanks for starting this thread.

What's next Ken?

Jim, the GW and Chiltern ATP schemes were pilots to try different ATP technologies as an overlay to the standard BR signalling. They were installed following a post-Clapham assurance by BR that ATP would be fitted (even though Clapham was not ATP-preventable). Railtrack redid the cost benefit analysis and showed that the costs of ATP as an overlay to the existing system were disproportionate to the benefits. Hence the development of TPWS which was intended as a short term interim measure pending roll-out of ETCS level 3, which was seen at the time to be about 5 years away (ie available by 2000). Well we all know what actually happened. With communications based systems such as ETCS level 2 and 3, ATP is essentially free (well, very little cost). ATP does prevent the low frequency high consequence events that TPWS cannot prevent, such as a high speed SPAD where TPWS may not stop the train before the conflict point. I have worried for the last 20 years about an ATP preventable accident on a TPWS section. Though as it happens the benefit of TPWS is now though to be rather higher than that used in the original analysis. If we were not to fit ATP when installing new signalling, in the event of an accident the consequences in court for those having made that decision would be dire, and rightly so. I accept that ETCS does have operational restrictions and I expect with wider implementation more work-a-rounds will be found.

Some observations: The Cambrian ETCS implementation was a pilot scheme. I would be very surprised if the installed system is to the latest hardware and software specifications. ETCS gives you ATP as an integral part of the system. While TPWS is good (disclaimer: I have an interest as I led the team that developed the concept and had it agreed by DfT and the Railway Inspectorate - other members of this forum were on the team), TPWS cannot provide the same protection against the low probability but high consequence events that ATP prevents. If you are re-signalling you really want ATP. ETCS is suitable for speeds above 125mph. It has been determined that lineside signals are not. ETCS would therefore allow some line speed increases on WCML/ECML. Until the end of next month at least, fitting of ETCS is a legal requirement when re-signalling (as opposed to maintenance replacement). Even after that there will be a strong commercial case for following the ETCS standards. (Though there would be an opportunity for minor deviations to allow something like the ETCS level 3 lookalike that Bombardier has implemented outside the EU). ETCS allows ATO which can give a more reliable timetable adherence in high density sections such as Thameslink core. With ETCS 2/3 you could, in theory, abandon all lineside signals, track circuits and axle counters. In level 3 particularly these serve no purpose except as a fall-back if the ETCS fails. But given that ETCS hardware is mostly duplicated with hot standbys on board and at wayside, system failures are rare. (Bangkok Skytrain uses a specifically designed metro version of ETCS and has no signals except in the depots, with no main line track circuits or axle counters). Removing the lineside systems reduces failures and costs.

No, which is one of the reasons why axle counters find favour. Neither track circuits nor axle counters are required with ETCS 2/3 but are provided for back up.

No, which is one of the reasons why axle counters find favour. Neither track circuits nor axle counters are required with ETCS 2/3 but are provided for back up.

But it’s not just a software change. The hardware would also have to change. New safety cases required so altogether a very expensive mod on a little used line.

Actually the reverse. Sand improves adhesion which allows the braking force to be transmitted through the contact patch without causing the wheels to slide. Wheelflats are caused by a locked wheel leaving an area of low adhesion and entering one of normal adhesion. The sliding friction at the interface then causes a metallurgical transformation of the steel in the wheel. The resultant compound, martensite, is hard brittle and cracked. It then spalls from the wheel leaving a depression that becomes a flat under the rolling action of the wheel. It is perfectly possible to have a flat on only one wheel of an axle if only one rail is heavily contaminated but flatting both is more likely.

Don't forget the 5 Brush class 48 locos. The only data panel I ever photographed was from one of these as I guessed it would not be around long.

At £10 per mile we could reopen everything! £10m per mile may be a ball park.

Somebody posted the answer to this recently. There was a Derby based set that retained the maroon livery well into the 70's...........now who posted that?

Actually most of the vehicles that I have been involved with in recent years - admittedly in Asia not UK - have inter-car anticlimbers as standard. All with monocoque construction. i understand the problems of Mk 1 construction where the sole purpose of the bodyshell was to keep the rain off the passengers........

Very interesting: thanks for posting. There doesn't seem to be any sign of anti-climbers. I wonder how that function is provided. Anybody know?

Thank you. That certainly shows access for up WR trains to the down MR lines. I must be thinking of the junction that allowed down WR trains from Stonehouse access to the up MR lines and into Eastgate and vice versa. I thought this was a relatively late addition. I wonder when the Tuffley Junction to Standish Junction was de-quadrified............presumably when Eastgate closed.

I think Standish Junction was a BR innovation to allow GW trains access to Gloucester Eastgate. Happy to be proved wrong. The 4 track section between Gloucester and Cheltenham would also be a good location for mixed LMS GWR working but the 4 tracking might have been very late in the day. In which case it would be a good location for a twin track line. I think you can add rebuilt Scots and 8Fs to the LM list with the 0-4-4T and S&D 2-8-0 as occasional visitors. GWR would include big prairies, pannier tanks, 43xx , 28xx and Granges.

The instructions IIRC have some prototype notes. Built to enable unfitted trains to contend with a severe gradient. Cannot check now as I’m not home for another two weeks.

I cannot believe that it has been nearly 6 months since I posted! For various reasons I never managed to get shots of the loco before it went to Warren Haywood for painting, and then Warren didn't get time to Photograph it before delivery, but these appeared in the ether earlier today. I have to say that Warren has done an excellent job. Now I need to make progress with Martin Finney 47XX!

A whole month for a loco build! Are you slowing up Ken?