165/6s won't be able to run Portsmouth-Cardiff

[whole diary]

[6 OF 2 redundant adjunct of unimatrix 01]

or the very tight platform clearance could now be deemed unacceptable

[northwesterntrains]

It is strange that back in the days of Thames Trains, CLPG had a class 166 charter from the Cotswold Line to Weymouth via the Castle Cary to Dorchester line that is shown in red.

There's a Pacer related clearance issue on the Blackburn-Clitheroe line that sounds similar.  Pacers can get to Clitheroe BUT they can't manage anything like Sprinter speeds on that section and consequently a Pacer would take 20 minutes+ longer and isn't officially cleared, eventhough it would get there unlike on the Buxton line, where Pacers also aren't cleared (this is because the gradient is too steep for a Pacer and would likely cause a Pacer to roll backwards when trying to move off without a driver error.)

Also special rules apply for excursions.  A 2007 rail excursion heading for the Heart of Wales line was halted before it got the HOW line because it was class 67 hauled and 67s aren't allowed on the Heart of Wales line without special Network Rail dispensation.  After a significant delay it got switched for class 37s and it was later discovered that the operator had obtained Network Rail dispensation.  The special dispensation may mean that the train has to comply with different speed limits to the ones that normally apply.

[JayMac]

As was the case with the Christmas/New Year blockade of Reading. HSTs^▸ (High Speed Train) were diverted to Waterloo and gauge clearance was a major issue on the line from Waterloo through Staines, Virginia Water and Chertsey to West Weybridge. There was no way that the HSTs could run at line speed on this route - I know - I was on one. We crawled through many stations at no more than 10mph.

[super tm]

Or maybe as Chiltern dont actually own any 166 they have never bothered to check the guage clearance for that route.  I know 165 and 166 are almost identical but until you actually send one down a route you cant be 100% sure everything will be OK. 

[IndustryInsider]

Or maybe as Chiltern dont actually own any 166 they have never bothered to check the guage clearance for that route. 

I'm fairly certain that 166's ran on the Chiltern Line back in 1994 when Marsh Bridge at Didcot was replaced over that Easter meaning a 2-hourly direct service from Oxford to Paddington calling at High Wycombe ran for several days.  Also, I don't remember crews being given specific instructions not to take a 166 over that route last Christmas, which I would have though they would have been given how allocation mistakes can sometimes happen.

Again, as we discussed recently, just because a route isn't currently certified doesn't necessarily mean that they are going to start ripping up platform edges, and even if they do it doesn't mean that it's nothing that a few thousand pounds might sort out.

[vacman]

The proposal is from what I hear, to get the Turbo's cleared for most routes, isn't much of a problem in most cases, some platforms in Cornwall had to have minor adjustments in the early 90's for 158's to be cleared (St Germans was one).

[Worcester_Passenger]

As a mere passenger, why on earth did the 165s and 166s get built to a non-standard size in the first place?

I suppose that the same comment applies to the platforms out of Waterloo - I remember travelling on an HST^▸ (High Speed Train) from Waterloo to Reading during some engineering diversions ten(?) years ago and being appalled by the diddly-dum slow speed. I'd assumed it was because we were following a stopping train (which we were). Perhaps we were following a stopping train because the Southern wanted to get their passengers off the platforms before the HST ripped them up (the platforms that is). Anyway, why haven't the platforms been (gradually) rebuilt to a standard size - they seem to get new edging at regular enough intervals.

[northwesterntrains]

As a mere passenger, why on earth did the 165s and 166s get built to a non-standard size in the first place?

For standard gauge you can either have a 150 type carriage (wider than units like 156 but 20m in length) or a 156 (longer than 150 carriages but narrower than a 156.)

A 165, 166 (plus similar electric units) have both the wider and longer carriage, making them non-standard so needing extra clearance.  I imagine this was done to get maximum capacity for platform lengths (3+2 seating isn't really practical in a narrower carriage.)

[FarWestJohn]

Didn't West Weybridge become Byfleet and New Haw in 1961?

Good video in 1946:

http://www.youtube.com/watch?v=VAwRKQ4Gh_g

[inspector_blakey]

For standard gauge you can either have a 150 type carriage (wider than units like 156 but 20m in length) or a 156 (longer than 150 carriages but narrower than a 156.)

Well that clears everything up, thanks for the elegant explanation...

As a mere passenger, why on earth did the 165s and 166s get built to a non-standard size in the first place?

Historically the Western Region has had a wider loading gauge than the other regions. Of course the track gauge in terms of the distance between the rails is identical at 4' 8.5" or 1435 mm, but the actual size of the vehicles that can operate is a little larger.

This goes back a very long way into the past, and I suspect may even be a hangover from Brunel's doomed broad gauge of 7' 0.25". Great Western steam locomotives were built to take advantage of the wider loading gauge, with large outside cylinders at the front end which were (and indeed still are on the rare occasions when Network Rail gauging engineers make a mistake in clearing the route for a steam charter) infamous for clipping platforms.

The HST^▸ (High Speed Train) fleet is more or less "go everywhere", since it was designed by BR^▸ (British Rail(ways)) to operate all over the country it conforms to a fairly standard loading gauge for rolling stock. However the 165/166 fleet was designed by BR for operation solely within the confines of the WR, and therefore it makes sense to take advantage of the more generous loading gauge to give a bit more space internally. Having said that, northwesterntrains' assertion that this is required for 3+2 seating is nonsense, as there are high-density suburban units operating all over the network that have 3+2 seating and aren't built to the WR loading gauge (450s are just one example).

Frankly this whole thread is a bit of a ridiculous storm in a teacup - although CDF^» (Cardiff - next trains)-PMH may not currently be fully cleared for Turbo operation, significant portions of it are already, and the modifications that would be necessary to allow the entire route to be cleared may well be fairly trivial in most cases - as vacman said, adjusting platform edges or repositioning ground signals here and there, for example.

[ChrisB]

Are there any tunnels? They'll be costly...

[inspector_blakey]

There certainly are - Severn Tunnel and Twerton Tunnel for a start, but they won't be a problem. I'm not familiar enough with the route further east to comment.

But you're making the assumption that the Turbos would be out of gauge for the tunnels. I'd bet money that they would not be and the issues are likely to be far more minor and tractable than reworking entire tunnels. After all, as pointed out above, Turbos have on occasion wandered far outside their natural habitat without problems.

[ChrisB]

What we're really saying here is that no one really knows for sure what work would be needed on which line, aren't we? -:)

[inspector_blakey]

That's an entirely fair comment, although I reckon there are gauging engineers at NR^» (Network Rail - home page) who either know the answer already or will be able to find out relatively easily.

The main thrust of my argument is that the OP^▸ (Original Poster / topic starter)'s original statement, that Turbo stock would not be able to operate Cardiff-Portsmouth just because it currently isn't gauge-cleared for the route, is almost certainly complete garbage.

[Electric train]

There are 2 loading gauges static and dynamic.  Static is the envelope of the rail vehicle when stationary.  The dynamic is when the verchil is on the move and speed comes into play with dynamic loading guage also the cant of the track has to be taken into account.  Also although not gauge envelope the unsprung mass on each axle and the axle loading has to be allowed for.

As Industry Insider said just because a unit is not cleared for a route does not mean it can not be.