GWR distant operating practice at Junctions

[Junctionmad]

Ive begun reading my new book, GWR Signalling Practice , its a big read 

But I was reading about the change in practice begun around 1907 , whereby distants were removed from facing junctions , such that distants only applied to the main line and not the low speed diverging route 

 

Hence the GWR presumably removed  many splitting distants from that time onwards 

 

Does this man the correct operating practice is the the remaining distant , ie a distant on a single  post , was never pulled off for the diverging route , the signal then acting as a fixed distant , irrespective of whether the subsequent splitting stop signals ( for the diverging route  were  pulled off.

 

 I had always assumed the the  distant signal  was pulled off if the diverging route  stop signals were also off in the normal manner as pertained to the main line , but this would seem contrary to the GWR arrangements from approx 1907 onwards 

 

Would it have always been the case the the train was checked at the splitting junction signal , for a slow speed diverging line , ie the driver would never be given a through signal for the diverging line in advance of arriving at the signal ?

 

Does that mean for higher speed diverging situations , splitting distants would have been provided , where there any such high speed diverging situations ?, before modern times ( ie post 1960-70) 

 

An example of Model railway practice , would be a train signalled clear through a platform loop , presumably  the distant ( back on the main line ) in this case would remain On, even though the section ahead is clear and all stop signals inc home and starter are clear , as the route is clearly low speed ???

 

 

thanks again 

 

Dave 

 

 

 

Edited November 13, 2019 by Junctionmad

[RailWest]

AIUI the situation, basically:-

 

1. If the speed of the diverging route was low, then any distants on the approach could only be cleared for the main route, and would remain at caution for the diverging route.

2. If the speed for the diverging route was high enough, splitting distants would still be provided.

[TheSignalEngineer]

For the diverging route if the speed lower than the main route the signal would usually be kept at danger until the signalman could see that the train had reduced speed sufficiently. As track circuiting spread it became customary on more inportant lines to put a short track circuit on the approach to the junction signal and not allow any diverging routes requiring a reduction to be cleared until the track circuit was occupied. There were exceptions to the delayed clearing of signals which were specified in local instructions. As signals were cleared sequentially, later enforced by sequential locking, the next stop signal would not be cleared until the junction signal had been cleared.

[The Stationmaster]

On 13/11/2019 at 11:46, Junctionmad said:

Ive begun reading my new book, GWR Signalling Practice , its a big read 

But I was reading about the change in practice begun around 1907 , whereby distants were removed from facing junctions , such that distants only applied to the main line and not the low speed diverging route 

 

Hence the GWR presumably removed  many splitting distants from that time onwards 

 

Does this man the correct operating practice is the the remaining distant , ie a distant on a single  post , was never pulled off for the diverging route , the signal then acting as a fixed distant , irrespective of whether the subsequent splitting stop signals ( for the diverging route  were  pulled off.

 

 I had always assumed the the  distant signal  was pulled off if the diverging route  stop signals were also off in the normal manner as pertained to the main line , but this would seem contrary to the GWR arrangements from approx 1907 onwards 

 

Would it have always been the case the the train was checked at the splitting junction signal , for a slow speed diverging line , ie the driver would never be given a through signal for the diverging line in advance of arriving at the signal ?

 

Does that mean for higher speed diverging situations , splitting distants would have been provided , where there any such high speed diverging situations ?, before modern times ( ie post 1960-70) 

 

An example of Model railway practice , would be a train signalled clear through a platform loop , presumably  the distant ( back on the main line ) in this case would remain On, even though the section ahead is clear and all stop signals inc home and starter are clear , as the route is clearly low speed ???

 

 

thanks again 

 

Dave 

 

 

 

GW practice wasn't - as far as I can find - written down unlike LMS practice (which in any case was rather different because of that Company's much more common use of splitting distants).  So in GWR practice (as in BR practice for timetabled trains diverting to a lower speed route) the normal practice was to pull off all relevant stop signals once the train had been accepted by the 'box in advance so a train approaching a junction where it was booked to be diverted through the lower speed route would be likely to find all the stop signals at clear as it approached.  as the driver was expecting in any event to be diverted through a lower speed connection he could obviously adjust the speed of his train accordingly and obviously the distant at caution menat he should be prepared to stop at the Home Signal standing at danger.

 

In 1919/20 there were moves on the GWR to restore splitting distants at junctions where delay could occur if a Driver was given no advance of being routed through the lower speed route.  This seems to have got nowhere although interestingly most of the junctions identified later got worked splitting distants when the GWR adopted the principle of having a worked distant for each route where the speed was 40mph or higher.

 

BR practice appears to have been wholly standardised in 1960 when the normal method for booked trains was to clear the stop signals when a train had been accepted by the 'box in advance if there was only a single distant which did not apply to the diverging route(s).  However if a train was not booked to cross to the diverging route it was required to be checked approaching the stop signals of the 'box controlling the junction.

[Junctionmad]

I ask because GWR signalling practice details a meeting of gwr superintendents in 1907 which determined on the back of BOt advice to do away with many of the distants protecting low speed diverging routes and replacing them with fixed distants. The import being that any operating distant now only referred to the main route and hence I would presume as you indicate the distant was not ( never) pulled off when the diverging route was set.  

[The Stationmaster]

On 16/11/2019 at 23:04, Junctionmad said:

I ask because GWR signalling practice details a meeting of gwr superintendents in 1907 which determined on the back of BOt advice to do away with many of the distants protecting low speed diverging routes and replacing them with fixed distants. The import being that any operating distant now only referred to the main route and hence I would presume as you indicate the distant was not ( never) pulled off when the diverging route was set.  

The distant, of course, could not be pulled off when the diverging route was set because the interlocking wouldn't allow it.  As was the case everywhere else a distant could only be lowered after all the relevant stop signals had been lowered.

[Junctionmad]

7 hours ago, The Stationmaster said:

The distant, of course, could not be pulled off when the diverging route was set because the interlocking wouldn't allow it.  As was the case everywhere else a distant could only be lowered after all the relevant stop signals had been lowered.

Yes indeed I’m aware of that. WhAt I referred to is that the gwr decided that no distant would be pulled off for low speed diverts even if all the stop signals were clear on the diverted route. Ie they treated the running distant as applying to the main line and for all other purposes it was treated as a “ distant fixed at caution “ 

 

as I understand it. 

Edited November 18, 2019 by Junctionmad

[The Stationmaster]

20 minutes ago, Junctionmad said:

Yes indeed I’m aware of that. WhAt I referred to is that the gwr decided that no distant would be pulled off for low speed diverts even if all the stop signals were clear on the diverted route. Ie they treated the running distant as applying to the main line and for all other purposes it was treated as a “ distant fixed at caution “ 

 

as I understand it. 

Correct.    GWR use of splitting distants was very limited following the decision to, in effect, reintroduce them but only where a turnout speed of a minimum of 40mph existed.  And still - it would seem - only where traffic conditions warranted having them.   Everywhere else it was either a distant worked for the principle route, provided its speed was 40 mph or greater or in some cases a single fixed distant but applying to every route through the junction if the speed of all of them was less than 40 mph.

 

But things changed over the years and in a number of cases when the distants were renewed as colour light signals in the 1960s they ceased to be splitting distants and could only show green for the fastest route through the junction. ( I specifically avoid using the words 'main route' or 'principle route' because in a number of cases the route to which the distant applied wasn't actually the one to the 'main line' because it wasn't the fastest route.

[TheSignalEngineer]

Aynho Junction was an example of changed circumstances where junction speeds and priorities was concerned. 

It had mechanical splitting distants when I first went there. The Bicester Line was still the principal route in those days, with a 70mph speed through the junction. The Oxford line was only 40mph. When the signal was renewed as a colour light it only worked for the Bicester line. After the Snow Hill direct expresses finished (except for one) the only traffic left on the Bicester line was an hourly DMU stopper. Meanwhile the Oxford line had taken the Class 1 passengers and was starting to get the Didcot MGR traffic and Southampton freightliners. All ow these trains were getting panned by not getting the distant then finding the Home off when they got to it. We dropped the speed of the Bicester line through the junction to 40mph and made the distant able to be cleared for either route.

[The Stationmaster]

15 hours ago, TheSignalEngineer said:

Aynho Junction was an example of changed circumstances where junction speeds and priorities was concerned. 

It had mechanical splitting distants when I first went there. The Bicester Line was still the principal route in those days, with a 70mph speed through the junction. The Oxford line was only 40mph. When the signal was renewed as a colour light it only worked for the Bicester line. After the Snow Hill direct expresses finished (except for one) the only traffic left on the Bicester line was an hourly DMU stopper. Meanwhile the Oxford line had taken the Class 1 passengers and was starting to get the Didcot MGR traffic and Southampton freightliners. All ow these trains were getting panned by not getting the distant then finding the Home off when they got to it. We dropped the speed of the Bicester line through the junction to 40mph and made the distant able to be cleared for either route.

You didn't by any chance the whole hog and have the splitting home worked by a single lever with the arm selected by the facing points?  If you'd done that you would have recreated exactly what the GWR did in the 1930s at Leigh Bridge when it provided an additional passing loop on the Minehead Branch.   However I don't think they ever applied that method at a physical junction.