hexagon789

Correct, no need for the cooling fan noises.

Underground Ernie is a UK children's TV programme, so the platform may be quite "childish" in some respects. The underground trains are all re-imagined Thomas the Tank-style with faces and personalities for a start.

They were supplied with dynamic, more correctly rheostatic brakes, but Irish Rail decided it was unnecessary and it was isolated pretty much from the beginning. To be fair they are two different forms of dynamic braking. The 201s have rheostatic brakes where the traction motors are reversed and become in effect generators, working to impede the trains motion. The current generated passes through a bank of resistors and the energy is dissipated as heat. The 29000s have a hydro-dynamic retarder, not entirely dissimilar to retarders in many modern buses. I'd need to look at the Journal which has details on the class, but often the issue with hydro-dynamic retarders is where the heat generated during braking is dissipated. Sometimes it's entirely through the transmission fluid other times the fuel tank is used as a heat sink. In GB, the Alstom Class 175 and 180 have hydro-dynamic retarders but both are isolated as particularly with the latter class it caused some fires. The Siemens Class 185 by contrast also has a hydro-dynamic retarder but it has never caused any problems on this class and remains in use.

Well then, surely if it's just pistons and liners that's not really changing the basic engine, so wouldn't the 567 sound still apply in the main?

Wasn't the original modifications purely the pistons and piston liners for reasons of parts standardisation rather than the engines themselves? If I am correct with that, then it would still be a 567 "under the hood" so to speak so I don't think those alterations would change the engine sound as such, the idle and max revs would be still those for a 567 engine so that difference from a 645 would still be there.

The IÉ Mk4 bogies look closer to the BR Mk4's SIG bogies than the CAF Mk5a ones. Underframe needs boxed in though whereas the CAF Mk5a have the various modules exposed more like Mk2 coaches. I agree the DVT is closer, though perhaps if the CAF 5a were 125mph as with the IÉ Mk4s the shape would be even closer, though the passenger accommodation doesn't really fit. In essence I can see +s and -s with both but I think the Hornby Mk4s are still a closer fit generally. The DVT is the main issue, I think though someone has done a modified nose for that which was exactly the right shape.

As Warbonnet says, that was cancelled due to Hornby producing their own one, so not in '00' but after cancelling that, they did say they were continuing with their 'N' gauge one. Afaik that hasn't been cancelled unless I've missed something.

I thought they had said something about the Mk4s but perhaps I'm misrecallling. They didn't do the full range anyway, missing the TOE and I think TOD vehicles, the four types covered being PO, SV, TO and DVT.

Cancelled because one of the big manufacturers came out and said they had one in the works as I recall. I've seen at least one repaint of Hornby Mk4s into the modern IÉ InterCity colours, if you are prepared to accept a number of visual differences then go for it. Certainly I don't think there is anything ready-to-run that is as close an approximation. The DVT is the greatest discrepancy though, the British Mk4 one has a raked angular front, the Irish one has more of a swept-back wedge shape.

I've read that as well, but I remain more interested in a period somewhat before I was born. Not to say I'm not interested in more modern stuff, early BR privitisation when many new liveries and trains burst into the scene interests me as well just not quite as much. If anything I look on the period with a degree of derisiveness and indeed amusement at many of the developments of the early 2000s. Seemed to be the era of new but rather short trains being introduced on improved frequencies which led to increased demand, which then outstripped supply because of the short trains and so on... Still find it interesting to reflect on Virgin Pendolinos being only eight-cars when new, when my local ScotRail 170s were all shiny and new in "toothpaste" livery and the era which led to the decline of loco-haulage in Ireland. Somehow the variety of the 1970s and 1980s interests me more even if it did begin the transition to fixed formation trains, at least there was still some variation. I reckon it would, just as modern British trains have done the same in the UK.

As someone considerably(!) younger than sixty, I feel I should perhaps make clear my exception to that "rule" and state that my primary period of interest is the 'Supertrain' era of approx late-1972 to 1987. This roughly coincides with my main period of interest in British Railways which is approximately the same.

Sorry, I didn't mean time imply facing points were the exception just that there's a few interesting examples where junction access is trailing against the direction of the main traffic flow Nice somersaults

I get that, just wondered if there was a prototype for it as such.

Trying to think of examples, but didn't Ballybrophy require reversal off the mainline to gain the line to Limerick via Nenagh from the Cork line for Dublin-Limerick trains when the Nenagh line was the mainline to Limerick? Also, the Midland Railway in Great Britain studiously avoided facing points wherever possible, Garsdale on the Settle & Carlisle required a double reversal to gain the branch to Hawes from the bay platform for example. Not sure if any Irish railway companies followed the same practice as the British Midland?

It's difficult to say, and I'm sure the RAIB will consider it in their report. British Rail did however do extensive testing with push-pull trains after a number of incidents, Polmont in 1984 being perhaps closest to this incident in nature. At Polmont a Mk3 Push-pull set propelled from the rear by a Class 47 struck a cow at 85mph which disintegrated and part of the carcass lifted the driving trailers lead bogie sufficiently for it to derail. It was concluded that push-pull trains were as safe as multiple units, but obstacle deflectors were fitted to mitigate this type of accident occurring again. It's worth noting that the Mk3 and Mk4 DVTs were deliberately ballasted to 45 tonnes to give increased residence compared to the 34 tonne Mk2f driving trailer involved in Polmont. The HST sets have a 70 tonne power car each end which should be even more resilient. As for the motive power continuing to push, as soon as the multiple working connectors are broken or an emergency brake application is made power is cut instantaneously, it would be more the mass continuing to push with momentum than traction power. Both power cars still power, part of the idea of using them being the vastly increased acceleration. The 170s they replace take (according to Eversholt) 400 seconds to reach 100mph. The short HSTs take a mere 150 seconds by comparison. Even if one power car fails, they can still outperform the Class 170. The exact cause hasn't been determined but what is clear is that upon derailing the leading power impacted a bridge parapet which of course caused rapid deceleration and the rest of the train to effectively jackknife across the line behind it.

You can see the colour difference very clearly against the AC stock in the third photo. Still a glorious sight thundering along at 75 though in spite of the Americans getting their paint mix slightly out!

A thing of beauty!

I think, as has been stated before, they only began to be paired once they were fitted out first multiple working. Before that you'd need a crew for each loco and with the extra cost for that presumably it was to be avoided unless unavoidable as it were, making it very rare or non-existent?

Yes, there was a landslip further south so the driver stopped the train as the line was blocked. Control gage permission to run wrong line, then cross over to the opposite track to head back to Stonehaven station to detrain passengers. The train had begun accelerating away from the 15mph crossover restriction over a distance of a mile up to the linespeed for HSTs of 75mph when it derailed so likely speed was in the region of 50-60mph as the short sets can really shift making 100mph in about 2.5mins from a stand. A very sad incident indeed, mercifully the local lockdown in Aberdeen appears to have been a good thing as passenger numbers on board were much lower than they might otherwise have been.

Sadly it's now been confirmed that three persons, including the driver, have died. My thoughts and condolences to all involved.

Earlier today a High-Speed Train running the 0638 ScotRail Aberdeen-Glasgow service derailed in the vicinity of Stonehaven. Unconfirmed reports of one or two deaths and multiple injuries. Thoughts with any affected in or by this terrible accident. Article on BBC News website contains some information but details remain sketchy at present: https://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-53751678

Thanks for that, I've obviously misunderstood what I read to mean only one driven axle rather than one motor driving three.

Given the steep gradients on parts of the Lebanese network I am a bit surprised these only had one driven axle it seems. Traction must've been "interesting" in poor rail conditions on a gradient.

Not my livery, for my time period anyway, but looks utterly stunning!

Excellent! Thank you very much for that ttc. I did presume it would likely be full or partly detailed in Feb '73 but after making assumptions previous I wanted to be doubly sure, so thanks for that.