On Fri, 16 Nov 2007 17:05:14 +0000, Tom Anderson wrote:

This is one of the things that absolutely baffles me about the
automated signalling systems that are being deployed now - why is it
the signalling system that makes decisions about how fast a train
should go, and not the train?

I take it you are happy with the concept of double yellows?

Yes.

This is basically very similar.

...

Could you explain how?

Don't double yellows mean the train has to be going below a certain
(specified) speed on reaching the next signal?

Not necessarily, because it depends on how well the driver knows the line.

That double yellow is warning him that the signal ahead is yellow, after
which he really has to think of slowing down.


"asdf" wrote in message
...
On Fri, 16 Nov 2007 17:05:14 +0000, Tom Anderson wrote:

Don't double yellows mean the train has to be going below a certain
(specified) speed on reaching the next signal?

On Wed, 21 Nov 2007, asdf wrote:

On Fri, 16 Nov 2007 17:05:14 +0000, Tom Anderson wrote:

This is one of the things that absolutely baffles me about the
automated signalling systems that are being deployed now - why is it
the signalling system that makes decisions about how fast a train
should go, and not the train?

I take it you are happy with the concept of double yellows?

Yes.

This is basically very similar.

...

Could you explain how?

Don't double yellows mean the train has to be going below a certain
(specified) speed on reaching the next signal?

Oh, hang on, i was thinking of double yellow lines. *headdesk* I have no
idea at all what a double yellow light means.

I've kind of lost track of this thread, but isn't it the case that the
freight trains can't use the automatic signalling because the speeds are
wrong for that kind of train? So that's rather different to the double
yellow situation.

tom

--
Vegetables, rice and peas.