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Class 800 - Updates


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TPWS can be used at any line speed, its just a question of placing the grids in the appropriate location for the speed limit you are trying to protect.

 

ATP is far too restrictive warbling off at the slightest thing!

 

If the 800s have to wait for ETCS so they can run at 125 then they are going to be waiting a very long time.

Edited by royaloak
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Not quite, the IEPs aren't fitted with ATP, only AWS/TPWS & ETCS.

Those intended for GWR are or will be, it's been referred to many times and can be seen in photos of the relevant cabs - just to the right of the former Ministers shoulder I believe though there are some clearer shots on the design companies website:

 

21110609155_61be47b2f6_z.jpg

InterCity Express Programme test train by Department for Transport (DfT), on Flickr

Edited by Christopher125
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The obvious question is why design the TPWS for 110 when the line speed is 125?

 

Because the 125mph is only applicable for ATP fitted trains, which are the majority of trains on the route, are protected when running at 125mph by ATP not solely by TPWS as with everywhere else.

 

Although I don't know the exact details, but seen as when the TPWS was installed, there were only a few units not fitted with ATP and capable of 125mph that would run out of Paddington, the extra expense of fitting loops that would stop a 125mph train (there is a big difference between the stopping distance for a 110mph train and 125mph train) was probably not worth the few minutes lost on a few journeys that resultant from restricting them to 110mph

 

This restriction may be relaxed for the IEPs due to their better braking characteristic, but I don't know.

 

Simon

Edited by St. Simon
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Those intended for GWR are or will be, it's been referred to many times and can be seen in photos of the relevant cabs - just to the right of the former Ministers shoulder I believe though there are some clearer shots on the design companies website:

 

21110609155_61be47b2f6_z.jpg

InterCity Express Programme test train by Department for Transport (DfT), on Flickr

 

Okay, fair enough, I hadn't realised that they were fitted, I must of missed somehow!

 

My apologies if I've confused people!

 

Simon

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The Chiltern Mainline interiors are overwhelming grey too, if anything more than the IEP, but I struggle to recall that ever being raised as an issue by enthusiasts.

Grey can look either dull and miserable or rather smart (and presumably everything in between), the devil's in the detail.

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Indeed. I wasn't that impressed looking in, but I think the windows are tinted so it's probably not fair to pass too much judgement like that.

And obviously everyone will have their own view.

Sadly not out of the windows in a lot of cases.

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May I offer a definite answer?

 

The GWR fleets will have it fitted, the other fleets will have a blanking plate fitted in both the speedo and input panel locations.

 

Both fleets will have ETCS capability, with it being left isolated until live. It currently provides a speedometer on the main screen. 

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800002 is grey with one end having red 'swirls & swooshes' and names of IEP stakeholders.

 

This was out on test this evening (approx 18:40) at Swindon, it left towards Bristol a few minutes later after siting in the centre road.

 

Simon

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*TPWS is only designed for 110mph where ATP is fitted, areas where ATP isn't fitted, then the TPWS is designed for line speed.

 

Simon

 

Can you add a bit more detail please Simon.

 

I understand ordinary TPWS is only good for up to 75mph and although it may be possible technically to increase this celling by moving the overspeed loops further away from the signal (and each other), I believe the design rules do not allow it. Thus above 75mph you need extra overspeed loops - which are (as you know) identified as TPWS+. On the BML these are all set to trigger if the train is doing 65mph and due to the EMU designed signal spacing they frequently end up being in the vicinity of the previous signal (i.e. the one showing a single yellow) - are you saying the GWML ones set to 110mph?.

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Can you add a bit more detail please Simon.

 

I understand ordinary TPWS is only good for up to 75mph and although it may be possible technically to increase this celling by moving the overspeed loops further away from the signal (and each other), I believe the design rules do not allow it. Thus above 75mph you need extra overspeed loops - which are (as you know) identified as TPWS+. On the BML these are all set to trigger if the train is doing 65mph and due to the EMU designed signal spacing they frequently end up being in the vicinity of the previous signal (i.e. the one showing a single yellow) - are you saying the GWML ones set to 110mph?.

I can add a little.

Going back 20+ years to when TPWS was under development Intercity trains (other than 125mph capable trains) had a design braking rate of 7%g and a service braking distance of 1740m (figures plucked form my memory) so that in a 4-aspect signalled area with a standard level track signalling spacing of 1020m there was a 300m (plus sighting distance) stopping contingency to allow for isolated brakes and low adhesion. The standard braking curve for 100mph stock was derived empirically from tests with a Deltic and a rake of mark 1's in shoddy condition including one vehicle with brakes isolated: the poorest condition that a rake would be allowed to operate at line speed without restriction. This W curve became the standard for setting brake performance. When HSTs came along, rather than having to resignal everything by increasing signal spacing (which would crucify capacity) or by adding a fifth aspect as was done for 140mph operation, the trains had to stop in the same distance as the earlier stock: hence the W125 curve and the requirement for 9%g braking on HSTs. Now the braking characteristics of cast-iron braked stock is very non-linear with speed and at lower speeds much higher braking rates are achieved. Hence the early disc braked EMUs were set with a design braking rate of 9%g so that they could match the braking distance of the old block braked stock. Disc brakes have an essentially constant braking rate independent of initial application speed.

So an early concern for TPWS designers was to set a system that could catch errant trains having different braking rates. As you note, as speeds increas the loops need to be set farther apart and more distant from the stop signal to be able to catch the train in time before it exceeds the overlap distance. But the difference in braking rates between the different types of train means that a train with better brakes can brake later than one with poorer brakes (Statement of the obvious). That means that if you designed the TPWS grids to catch a train with the lowest permissible braking rate at the 110mph line speed you would certainly catch a 125mph train that was under control. So the design has to be a compromise as to where to fit the loops.

The TPWS development team sought to add to TPWS with a 'Yellow Speed Trap' as well as the standard 'Red Speed Trap' and 'Train Stop' functions. This became TPWS+ when it was realised that TPWS wasn't going to be a short term interim measure pending roll-out of ETCS.

The 75mph figure comes from the speed that a train can legitimately be doing at the yellow signal warning of the red ahead and still be under control. At higher speeds the first speed trap loops have to be located before the yellow.

This is a long winded way of saying that an inherent limitation of TPWS is its inability to cope with vastly different braking rates. As the fleet has become more uniform with a standard 9% brake rate then TPWS can be extended to higher speeds but freight (and steam specials) will always be a problem.

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Would any be eligible for transfer under TUPE?

 

No - as it's a totally different concern doing a different job it could not be categorised as a takeover of existing work and the staff doing it.

 

However to be blunt TUPE is barely worth the paper it is written on as has been seen on a number of occasions in the railway industry.  Yes it, in effect, 'guarantees' that your new employer - who has taken you over with the business  - will continue your existing employment terms and conditions.  However what it doesn't prevent, in the letter of the wording, is the new employer deciding to introduce new employment conditions and bringing them into effect, and that is exactly what has happened in some cases by simply continuing the old conditions for a few months then introducing new ones.

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No - as it's a totally different concern doing a different job it could not be categorised as a takeover of existing work and the staff doing it.

 

However to be blunt TUPE is barely worth the paper it is written on as has been seen on a number of occasions in the railway industry.  Yes it, in effect, 'guarantees' that your new employer - who has taken you over with the business  - will continue your existing employment terms and conditions.  However what it doesn't prevent, in the letter of the wording, is the new employer deciding to introduce new employment conditions and bringing them into effect, and that is exactly what has happened in some cases by simply continuing the old conditions for a few months then introducing new ones.

I'm being transferred under TUPE at the moment, and it's truly awful, a soul destroying process. it's just.....everything. Take Jury service, going from my existing employer paying our wages in full, to our new employer asking us to claim statutory from the courts. Over a long trial, that will cost you your home. I've lost 10 days extra TA/ACF leave. But they are asking us to relocate from London to Sunderland, so our current jobs can be done by Indian Nationals living in a barracks in Tilbury, so with 4 kids settled in schools and the Wife working, that's me down the DHSS in fairly short order. Yep, that TUPE thing really works. 

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No - as it's a totally different concern doing a different job it could not be categorised as a takeover of existing work and the staff doing it.

 

However to be blunt TUPE is barely worth the paper it is written on as has been seen on a number of occasions in the railway industry.  Yes it, in effect, 'guarantees' that your new employer - who has taken you over with the business  - will continue your existing employment terms and conditions.  However what it doesn't prevent, in the letter of the wording, is the new employer deciding to introduce new employment conditions and bringing them into effect, and that is exactly what has happened in some cases by simply continuing the old conditions for a few months then introducing new ones.

 

It's happened to me twice, when getting privatised.

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Has any information been released on the interiors for the new units yet?  I think the only photos I have seen have been of the Virgin units.  I am very interested to see if GWR will be bringing forward their fantastic first class seats from the mk3s, or if we will be stuck with an inferior product.

 

Without doubt the current first class seat is the finest in Europe and it will be a real shame for it to take a step backwards as a result of some sort of DFT led specification....

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According to the latest Todays Railways the first sets are going to be used on the North Cotswolds Line.   This will at least give them the least mileage on the main line on diesel power.  Also as the GWR sets were ordered by DaFT I suspect that they have specced the interior rather than GWR.   There are several interior photos of the first UK assembled set in the article.

 

Jamie

Edited by jamie92208
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The Virgin interior - seat design looks the same, just the covers differ. The red fabric used in Standard Class on the HST/225 isn't holding up that well, showing marks already and as for the chewing gum worked into the carpet - what a damning indictment on the attitude of todays traveller on the property of others.

 

Being DfT specified the only regional variance will, it seems, be colours.

 

Virgin-Azuma-interior-of-first-class.jpg

Edited by Richard E
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