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Author Topic: New Train  (Read 3485 times)
Tim
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« Reply #30 on: November 21, 2017, 04:50:37 PM »

This may not be correct, but my impression was that although the unmuzzling of the 800s brought their total power up to the level of the 802s but that they were still subject to acceleration restriction not applicable to 802s. 

I am ready to be corrected,   
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« Reply #31 on: November 21, 2017, 11:57:48 PM »

Out of interest, do you think its likely in the future that the Reading to Paddington section will be increased from 125mph to 140mph, I know its happening on East Coast, but I'm sure GWR wanted to look at doing it too!
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bignosemac
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« Reply #32 on: November 22, 2017, 02:02:55 AM »

Is a speed increase happening on the East Coast Main Line?

As far as I'm aware there are aspirations, but no firm plans yet. In cab signalling is being fitted to trains on the ECML, but Network Rail haven't committed to other infrastructure improvements to allow speed increases. The focus is on line capacity improvements, not top speed increases.
« Last Edit: November 22, 2017, 02:46:34 AM by bignosemac » Logged

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grahame
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« Reply #33 on: November 22, 2017, 07:19:21 AM »

The focus is on line capacity improvements, not top speed increases.

Signalling changes - ERTMS? - which remove what I call "absolute block" but probably has a more technical name - should allow a closer headway between trains.   Big question as to what happens at each end of such close headway sections; Reading "sprays" them out better than they use to.  Flat crossings in and out of Paddington platforms may become the limiter - very tight at times already; coming in last night, good run all the way up from Wiltshire until a signal halt outside the terminal.

Another capacity increase can be gained by longer trains, but there gets to be a point at which the benefits drop away; already reports of 5+5 IETs with imbalanced loads.  I heard reports where 10 to 12 car increases have been made on London other lines that the two extra carriages have been added at the outer (country) end and not at the London end where the trains overcrowd and it's really needed, and of course longer trains take longer to pass over junctions and through speed restriction sections. Again at Paddington , there are issues as to how you could lengthen all but a few platforms.
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SandTEngineer
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« Reply #34 on: November 22, 2017, 10:00:04 AM »

Sometimes lower overall linespeeds mean increased capacity as braking distances are shorter and signal sections can be closer together.  The lines south of London are a good example of that.  Same applies to ETCS.

The Southern Railway discovered that having lines paired by direction (i.e. UP SLOW/UP FAST/DOWN FAST/DOWN SLOW) was the best option for open stretches of main line, but paired by use (i.e. UP FAST/DOWN FAST/UP SLOW/DOWN SLOW) worked better for capacity at the approach to major terminal stations (a good example being the switch from one method to the other at Wimbledon Flyover on the SWML).

Whoops, topic creep........ Roll Eyes

Note to Grahame: The signalling control element of ERTMS is ETCS https://en.m.wikipedia.org/wiki/European_Train_Control_System
« Last Edit: November 22, 2017, 05:22:09 PM by SandTEngineer » Logged

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Bmblbzzz
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« Reply #35 on: November 22, 2017, 10:13:28 AM »

The focus is on line capacity improvements, not top speed increases.

Signalling changes - ERTMS? - which remove what I call "absolute block" but probably has a more technical name - should allow a closer headway between trains.   Big question as to what happens at each end of such close headway sections; Reading "sprays" them out better than they use to.  Flat crossings in and out of Paddington platforms may become the limiter - very tight at times already; coming in last night, good run all the way up from Wiltshire until a signal halt outside the terminal.

Another capacity increase can be gained by longer trains, but there gets to be a point at which the benefits drop away; already reports of 5+5 IETs with imbalanced loads.  I heard reports where 10 to 12 car increases have been made on London other lines that the two extra carriages have been added at the outer (country) end and not at the London end where the trains overcrowd and it's really needed, and of course longer trains take longer to pass over junctions and through speed restriction sections. Again at Paddington , there are issues as to how you could lengthen all but a few platforms.
Imbalanced loads? As in one 5-car section is crowded, the other empty? Or imbalanced in some other way?
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Thatcham Crossing
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« Reply #36 on: November 22, 2017, 10:59:00 AM »

Coming along the down main out of Paddington to Reading, in a non-stop Turbo (at full chat) the other day, when a 2 x 800 set passed us going up. Can't say at what speed, but it was shifting and passed us very quickly.

Very noticeable how much less buffet/air disturbance there was from the 800's compared to the HST that passed us a few minutes later.

If nothing else, I guess aerodynamics have improved in the last 40 years!
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chrisr_75
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« Reply #37 on: November 22, 2017, 11:15:45 AM »

I heard reports where 10 to 12 car increases have been made on London other lines that the two extra carriages have been added at the outer (country) end and not at the London end where the trains overcrowd and it's really needed

 Grin Grin
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chrisr_75
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« Reply #38 on: November 22, 2017, 11:19:15 AM »

Imbalanced loads? As in one 5-car section is crowded, the other empty? Or imbalanced in some other way?

Everyone sat on the left, causing the train to list over to that side  Wink
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grahame
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« Reply #39 on: November 22, 2017, 04:33:54 PM »

Imbalanced loads? As in one 5-car section is crowded, the other empty? Or imbalanced in some other way?

Everyone sat on the left, causing the train to list over to that side  Wink

Yes to the first, no to the second.   Crammed at London end, space at country end.

I WAS once on the paddle steamer on the Clyde and the Captain announced we were passing the royal yacht on the left hand side ... everyone rushed over and the next request was for some people to move back as we had lifted the right paddle wheel out of the water!
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chrisr_75
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« Reply #40 on: November 22, 2017, 05:04:16 PM »

Imbalanced loads? As in one 5-car section is crowded, the other empty? Or imbalanced in some other way?

Everyone sat on the left, causing the train to list over to that side  Wink

Yes to the first, no to the second.   Crammed at London end, space at country end.


The HST's are often the same, though at least the contents can be re-distributed within a little easier than with a 2x5 IET.

I have noticed if there is an imbalance on a Turbo leaving PAD, it's usually the other way round, country end busy, London end quiet(er).
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Four Track, Now!
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« Reply #41 on: November 22, 2017, 06:38:21 PM »

That won't please the Yorkshire man I met after his first trip on the Class 800. He told me "Well they're not Voyagers" which was apparently a good thing. Also said the seats are "Rock-Ard" and he didn't like them so I doubt he'd manage the trip to Penzance comfortably.

Did he ask the trolley operator "Ow much???"

(I come from Lancashire).
« Last Edit: November 22, 2017, 07:27:51 PM by Four Track, Now! » Logged

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stuving
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« Reply #42 on: November 22, 2017, 06:52:08 PM »

Coming along the down main out of Paddington to Reading, in a non-stop Turbo (at full chat) the other day, when a 2 x 800 set passed us going up. Can't say at what speed, but it was shifting and passed us very quickly.

Very noticeable how much less buffet/air disturbance there was from the 800's compared to the HST that passed us a few minutes later.

If nothing else, I guess aerodynamics have improved in the last 40 years!

Now, would there be anything about that in the requirement, do you think? Of course there is!
Quote
3.17 Aerodynamics & Pressure Effects
TS361
The internal pressure changes within IEP Trains must not exceed 4kPa over a 4 second period under any conditions on the IEP Network, including operation in single bore/track tunnels and 2 single IEP Trains passing in twin track tunnels.
TS1994
In addition to complying with the requirements set out in the TSI, the IEP Trains must exert no more than 1.44kPa peak to peak pressure on a train on an adjacent track when the IEP Train is travelling at all speeds on a windless day in open air on open track.
TS1995
The IEP Trains shall meet the requirements of Railway Group Standard GM/RT2142, Issue 3, August 2009, ‘Resistance of Railway Vehicles to Roll Over in Gales’ without modifications to the infrastructure.

Could you judge if the pressure from that passing HST was more than 1.44 kPa peak to peak? (That's the weight of two forum members per square metre, if that helps. The right two, obviously.) Maybe not.

I understand that it is reducing the pressure "slam" going into or out of a tunnel, in particular, that has led to trains getting pointier noses recently. Though in the case of GWR's 800s, it may have more to do with the veracity of adverts for them.
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1st fan
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« Reply #43 on: November 22, 2017, 10:44:14 PM »

That won't please the Yorkshire man I met after his first trip on the Class 800. He told me "Well they're not Voyagers" which was apparently a good thing. Also said the seats are "Rock-Ard" and he didn't like them so I doubt he'd manage the trip to Penzance comfortably.

Did he ask the trolley operator "Ow much???"

(I come from Lancashire).

Don't know about that Wink but he didn't fancy the "Bloody instant stuff" when asked if he wanted anything from the trolley Grin. I suspect he wasn't offered a filter coffee given he said he didn't buy anything.
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devonexpress
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« Reply #44 on: November 22, 2017, 11:57:48 PM »

Sometimes lower overall linespeeds mean increased capacity as braking distances are shorter and signal sections can be closer together.  The lines south of London are a good example of that.  Same applies to ETCS.

The Southern Railway discovered that having lines paired by direction (i.e. UP SLOW/UP FAST/DOWN FAST/DOWN SLOW) was the best option for open stretches of main line, but paired by use (i.e. UP FAST/DOWN FAST/UP SLOW/DOWN SLOW) worked better for capacity at the approach to major terminal stations (a good example being the switch from one method to the other at Wimbledon Flyover on the SWML).

Whoops, topic creep........ Roll Eyes

Note to Grahame: The signalling control element of ERTMS is ETCS https://en.m.wikipedia.org/wiki/European_Train_Control_System

That is true about slower speeds, but then if trains are faster then more services can run just a greater distances apart. I wouldn't be surprised in the future if the old Paddington Parcel depot(now a car park) is made into platforms. As for the up down thing, the Great Western is split with the fast lines together, slow lines together, all the way from Paddington to Didcot. The issue is mainly down to trains coming in late, staying in Paddington longer than booked, and then causing further delays. With the new IET's taking over HSTs timings should improve(which is being seen, and will get better as time goes on) however, the timetable change next year could be an issue, as whilst its taking full benefit of the IET acceleration, is it leaving enough time for a late service to catch up when running late?
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