140mph Virgin train set for Hertfordshire lines is dangerous

[61653 HTAFC]

Clearly this woman is worried that her son (who is a grown man by the way) won't be able to wave at her or at 140, or she won't be able to see him wave... Slow news day.

 

[Dent]

Some of Hertfordshire's local papers (and probably those in other areas too) have a very parochial attitude. When I was working for Hertfordshire CC about twelve years ago, I was told that when news about the Hatfield rail crash reached one of the papers in the east of the county, their initial view was not to run it because it was in Hatfield, and they were in Ware or Bishops Stortford.

Focussing on local news is rather the point of local newspapers. It's not a "parochial attitude" to focus on what is relevant to their remit.

 

[Mag_seven]

Clearly this woman is worried that her son (who is a grown man by the way) won't be able to wave at her or at 140, or she won't be able to see him wave... Slow news day.

Will since he is a VTEC driver I would rather hope so!

 

[Bald Rick]

Presumably steering a Virgin train gets even more difficult at 140mph.

 

[3141]

Focussing on local news is rather the point of local newspapers. It's not a "parochial attitude" to focus on what is relevant to their remit.

Hmm. They couldn't have known just how big an effect on the whole railway system the Hatfield crash was going to have, but they might have realised that though it was 12 or more miles away there'd be people in their area who'd be affected by it, which would make it "relevant to their remit".

 

[Spartacus]

a literal reading of this thread would imply that an HST set has a shorter braking distance than an equivalent loco-hauled Mk3 set. Is that right?

I doubt a loco hauled Mk3 set would be much different to a HST of the same length and speed, but at the time there were deltics, 50s and other quick locos rushing around hauling Mk1s and Mk2s (plus the odd carriage of big 4 origin) at 100mph, which would take longer top stop from 100mph than a HST from 125mph.

 

[zn1]

140 operation is perfectly feasible without ETRMS, TVM430, the brakes on 225 sets SHOULD be able to cope with braking distances, as should a 91.

a extra signal aspect. with LED Signalling now the standard flashing greens or an orange green aspect to advise shouldnt be an issue

with regards to current pathing on ECML one suspects its not that viable, with headways needing increasing etc...

so keeping at the fleets at 125 MAX is more than adequete, the extra 15mph, isnt really worth it for the time it would save in long term, Unless 140mph cruising can be sustained for desired periods of time to make it viable...one suspects not ..at the moment

 

[najaB]

140 operation is perfectly feasible without ETRMS, TVM430...

Depends on your definition of 'feasible'. There's no reason that it can't be done based on braking distances, but signal sighting at >125mph is, apparently, a concern.

 

[edwin_m]

Depends on your definition of 'feasible'. There's no reason that it can't be done based on braking distances, but signal sighting at >125mph is, apparently, a concern.

Also AWS would be inadequate. If you kept the bell for the green as well as the flashing green then 140mph trains would receive no audible warning of the need to slow to 125mph - a particular risk given the reduced sighting distance. If a steady green aspect sounded the warning then there would either be an inconsistency between the 140mph route and other routes, or all trains on other routes would get a warning at every signal.

As a bare minimum the trackside equipment on 140mph routes and all 140mph traction would have to have some additional AWS function to distinguish between flashing and steady green, which didn't affect the normal AWS function for other trains and routes.

TPWS would also need re-assessing with the possible need for yet another overspeed sensor. By the time you've done all that you might as well just fit ERTMS anyway.

 

[Ianno87]

Depends on your definition of 'feasible'. There's no reason that it can't be done based on braking distances, but signal sighting at >125mph is, apparently, a concern.

It gets to the point at which signals are coming at you so thick and fast, it's difficult to process one to the next.

Plus, at 140mph, to give 8 seconds sighting time, all signals would have to (by my lunchtime mathematics) have an unobstructed view from around 550 yards away (around 500 metres). That in itself is a substantial infrastructure design challenge.

 

[Roast Veg]

Interesting to hear the specifics of why 140mph running is difficult without in cab signalling. Presumably the fact that in the 4 track sections of the ECML the fasts are in the middle makes signal sighting easier, as obstructions are less likely?

 

[jopsuk]

I'm pretty sure that it comes from British Railways (and other) research- the issue being the ability to see and process lineside signals fast enough. Even on the 4-track sections of the ECML there are bridge piers, stations, curves, tunnels that cause obstructions

 

[gsnedders]

AFAIK few other places in Europe allow 125mph running without in-cab signalling (well, to be pedantic, I think the UK is the only place that does, though some others allow 200 km/h which is 124.andabit mph); limits without in-cab signalling vary from 80 km/h to 200 km/h (~50mph to ~125mph) as far as I'm aware.

 

[Peter Mugridge]

AFAIK few other places in Europe allow 125mph running without in-cab signalling (well, to be pedantic, I think the UK is the only place that does, though some others allow 200 km/h which is 124.andabit mph); limits without in-cab signalling vary from 80 km/h to 200 km/h (~50mph to ~125mph) as far as I'm aware.

Until July... SNCF run TGVs on the classic line between Tours and Bordeaux at up to 135mph; I think that's conventionally signalled...?

 

[gsnedders]

Until July... SNCF run TGVs on the classic line between Tours and Bordeaux at up to 135mph; I think that's conventionally signalled...?

Ah, yes, there's the small number of upgraded lines in France where they run at 220 km/h (c. 137mph). They have some altered form KVB as in-train supervision, but I've never been totally clear about the detail, which makes that strictly more powerful than AWS (KVB in general provides a "never exceed" speed communicated via beacons along the track).

From memory where they allow speeds above 160 km/h with an extra signalling aspect (a flashing green, meaning slow down to 160 km/h if faster), but I can't quickly find any detail about that?