Virgin trains to travel at up to 135mph?

[Arthur Figgis]

Willms wrote:
> Am Sat, 4 Jul 2009 09:31:32 UTC, schrieb "Paul Scott"
> <notvalidpmscott@***************> auf uk.railway :
>
>> Isn't the problem (much discussed here) that because they chose flashing
>> green as the 5th aspect it needed significant additional sighting
>> distance/time - presumably at least a doubling (and more for the 140/125
>> ratio). Perhaps if they had chosen double green it could have worked - but
>> that would have needed additional signal heads, and it was an attempt to
>> provide a fifth aspect on the cheap?
>
> Methinks that higher speeds, even above 160 km/h (100 miles/hr),
> should only be driven with in-cab signalling and train-control. The
> ability to recognize and follow line-side signals is not stretchable
> to the infinite.

Before we starting slowing the trains down we should ask how many
accidents have resulted directly from 125 mph running in the past
(however many) years.

--
Arthur Figgis Surrey, UK

[Jonathan Morton]

"Paul Scott" <notvalidpmscott@***************> wrote in message
news:iIOdnQkOyK_Kv9LXnZ2dnUVZ8vWdnZ2d@bt.com...
>
> Isn't the problem (much discussed here) that because they chose flashing
> green as the 5th aspect it needed significant additional sighting
> distance/time - presumably at least a doubling (and more for the 140/125
> ratio). Perhaps if they had chosen double green it could have worked -
> but that would have needed additional signal heads, and it was an attempt
> to provide a fifth aspect on the cheap?

Although I think that anything above 125 is a non-starter without in-cab
signalling, presumably the new LEDs with two "lights" could show double
green?

Do the TGVs use conventional signalling on those stretches of classic line
where they are permitted to run at 220 km/h?

Regards

Jonathan

[Tony]

On 5 July, 10:29, "Jonathan Morton"
<jonathan.mortonbutignorethisp...@*************** > wrote:
> "Paul Scott" <notvalidpmsc...@***************> wrote in message
>
> news:iIOdnQkOyK_Kv9LXnZ2dnUVZ8vWdnZ2d@bt.com...
>
>
>
> > Isn't the problem (much discussed here) that because they chose flashing
> > green as the 5th aspect it needed significant additional sighting
> > distance/time - presumably at least a doubling (and more for the 140/125
> > ratio). *Perhaps if they had chosen double green it could have worked -
> > but that would have needed additional signal heads, and it was an attempt
> > to provide a fifth aspect on the cheap?
>
> Although I think that anything above 125 is a non-starter without in-cab
> signalling, presumably the new LEDs with two "lights" could show double
> green?
>
> Do the TGVs use conventional signalling on those stretches of classic line
> where they are permitted to run at 220 km/h?
>
> Regards
>
> Jonathan

Also, what is the situation in Germany where ICEs run at high speed on
stretches of classic line - is cab signalling always used there? I was
recently on an ICE between Aachen and Cologne which reached a top
speed of almost 250 km/h. As far as I'm aware this line is not an HSL
and is shared with other traffic, but I may be wrong...

Tony

[Tony Polson]

Tony <th_1977@***********m> wrote:
>
>From what I can find out about LZB from a quick search online, it has
>been in operation since the mid-70s and is deployed on quite a few
>lines in Germany. Why did Network Rail/BR not consider introducing
>such a tried and tested system to allow speeds in excess of 125mph on
>classic lines such as the WCML? It seems to have the advantage that
>the existing track-side signals could remain and still be used by
>trains not fitted with LZB. Surely it would not have been
>prohibitively expensive?

After the fiasco with the proposed moving block signalling for the WCML,
it was probably a desire to use something tried and tested rather than
try yet another "new" technology - in which "new" means, in this case,
something more like "not previously tried in Britain".

The UK was formerly well known for "not invented here" syndrome, in
which technologies that had been tried and thoroughly tested elsewhere
didn't get a look in unless they were also tried and thoroughly tested
here before use. It is understandable; our railways have an outstanding
safety record and no-one wants to put that at risk.

Of course all caution was then thrown to the wind with the applications
of moving block signalling, first to the Jubilee Line Extension and then
to the WCML upgrade. In each case, moving block was a complete disaster
and conventional signalling had to be substituted in great haste.

Given those disastrous decisions, it is not surprising that signalling
professionals reverted to something that was well tried and very
thoroughly tested, and there certainly wouldn't have been an opportunity
to try yet another "new" technology such as LZB. Let's not forget that
TPWS had only recently been added as an overlay to conventional
signalling nationwide, and was still settling in, so LZB would have been
just another complication on top.

[allan tracy]

> * London - Scotland (i.e. Glasgow or Edinburgh) under four hours --
> isn't that already thoroughly convincing?
>

As rail still only enjoys the smaller proportion of the Anglo –
Scottish market, compared to air, I would guess that many nowadays
would argue that it’s not convincing enough.

[allan tracy]

>
> * Methinks that higher speeds, even above 160 km/h (100 miles/hr),
> should only be driven with in-cab signalling and train-control. The
> ability to recognize and follow line-side signals is not stretchable
> to the infinite.
>
> * Let them introduce ETCS, or maybe TVM430 or LZB, if something proven
> is wanted, but not try to add one more baroque twirl to line-side
> signals.
>

But it is important to remember, at its simplest, the safety case
requires only that the line side signal aspects be available within
the cab and that those aspects can, as necessary, override the
driver’s control of the train.

All of those systems provide this but, in terms of the basic
requirement, at highly expensive overkill.

Whilst the debate continues only in terms of unnecessary and expensive
complex, all singing all dancing, signalling solutions the business
case for moderate increase in speed will just never add up.

We should therefore be looking at cheap signalling solutions that
could do so and certainly not be using the un-affordability of
something far more complex as an excuse for throwing in the towel.

[allan tracy]

>
> However, would it be worthwhile fitting this for a relatively short
> period before the lines are fitted with higher Levels on
> resignalling? I don't think so, especially in view of the capacity
> restrictions it would introduce, but YVMV.
>

I prefer to look at it optimistically in that an upgrade to 135/140
mph running would be just a stopgap until HS2 comes along.

Hence, the solution needs to be cheap and, as far as speed is
concerned, the last such upgrade that the existing main lines would
require.

[Tony Polson]

allan tracy <allandetracy@live.co.uk> wrote:
>
>I prefer to look at it optimistically

You mean, with a complete absence of any resemblance to reality.