"Ar" <Ar@127.0.0.1> wrote in message
news:4887b134$0$2519$da0feed9@news.zen.co.uk...
> On Tue, 22 Jul 2008 11:16:40 +0100, BH Williams wrote:
>
>> TVM signals are carried by the track circuit, and give a maximum
>> permitted speed, rather than being a repetition of signal aspects. These
>> speed bands vary according to the type of train, gradient etc, and are
>> not directly related to the location of the repere.
> <snip>
>
> Thanks for your very detailed reply, none of this was explained in the
> commercial DVD, as they were more focused on generalities and the view
> from the Eurostar cab.
Thanks are due to my wife, who has explained it innumerable times at
presentations to the IEE,IET, groups of students etc. Believe me, that was
the simplified, abbreviated explanation......
Brian