Routeing Guide Question - Maps and doubling back

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HowMuch?

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After lurking here for so long, I think I'm getting the hang of Routeing now.

One thing I've never seen stated explicitly, though it is implied by the routeing solutions people offer, is whether the maps give all the information necessary to check that a proposed permitted route does not involve doubling back ?

- I ask because the rule about doubling back seems to apply to any station, but the routeing guide only shows routeing point stations (and groups).

I guess :? this is covered (at least in part) by the fact that many of the stations not shown on the maps are those within routeing groups. (Stations in a group are always OK for doubling back through 'for interchange purposes'.)

But is it definite that there are no other 'invisible' stations that can cause a doubleback 'trap' unless you also look at the full network map?
 
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MikeWh

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Maps BS, CG, CS, LM and NW all contain a hidden gotcha just South of Preston called Leyland.
 

yorkie

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The answer has to be no; the Routeing Guide maps do not contain that information. The only way they would contain that information is they showed stations that are between the junction at which routes converge and Routeing Points.

Doubling-back on maps is not permitted, except when permitted by an easement and/or when permitted by the Group Stations rule, and also except where the route shown on the map is also permitted by the shortest route rule.

For example York-Hull is permitted to double-back between Micklefield & Leeds (Group Station rule), Peartree-Tamworth is permitted to double-back between Peartree & Derby (Shortest route rule; not using the Routeing Guide and therefore not using the maps), and Bromsgrove-Bristol is permitted to double-back between Bromsgrove & Birmingham (easement).
 

HowMuch?

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Thanks, Yorkie and MikeWh. That was really illuminating.

I was beginning to wonder if I'd asked a stupid question. I'm glad it wasn't.

"The Routeing Guide In Detail" mentions doubling back quite a lot. But all the pictorial examples it gives of how to spot doubling back all look like extracts from RG maps - with no mention of having to refer to a full network map. You can see why I was leaning towards thinking that the RG Maps were all that were needed.

Also, I'd noticed how people on here respond to a request to check a permitted route. After the usual checking for direct trains / short(ish) route, and for valid routeing points and maps, they will say "the route you suggest is shown on maps AB+XY and is therefore valid". They DON'T go on to say "and I've checked with the full network map that no doubling back is involved".

You've made me think about this a bit. I'll ask some more later if I may?
 

hairyhandedfool

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The Routeing Guide defines doubling back (in Step 7 of the Instructions) as "passing through the same station twice on a single journey". No mention of routeing points (or groups) or maps.
 

exile

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In other words the RG cannot be used to find valid routes if doubling back is an issue on the route you wish to find is or is not valid. You have to have an additional and map showing the topography of the rail network. Carnforth is an interesting case - if you pass through on the main line which has no platforms have you actually "passed through" the station or not?
 

All Line Rover

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Maps BS, CG, CS, LM and NW all contain a hidden gotcha just South of Preston called Leyland.

Damn! <( That station is almost as annoying as Wolverton. :( No wonder the journey planner refused to work for a certain journey. Time to adjust my list! :lol:

EDIT: At least some backups are available. ;)
--- old post above --- --- new post below ---
"The Routeing Guide In Detail" mentions doubling back quite a lot. But all the pictorial examples it gives of how to spot doubling back all look like extracts from RG maps - with no mention of having to refer to a full network map. You can see why I was leaning towards thinking that the RG Maps were all that were needed.

Also, I'd noticed how people on here respond to a request to check a permitted route. After the usual checking for direct trains / short(ish) route, and for valid routeing points and maps, they will say "the route you suggest is shown on maps AB+XY and is therefore valid". They DON'T go on to say "and I've checked with the full network map that no doubling back is involved".

You've made me think about this a bit. I'll ask some more later if I may?

Yes I agree it's a pain and it isn't at all clear from the instructions that you must consult other documents in additional to those from the Routeing Guide.

A new station opening could theoretically change the validity of a ticket without any change to the Routeing Guide whatsoever!
 

wintonian

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In other words the RG cannot be used to find valid routes if doubling back is an issue on the route you wish to find is or is not valid. You have to have an additional and map showing the topography of the rail network. Carnforth is an interesting case - if you pass through on the main line which has no platforms have you actually "passed through" the station or not?

If you travel through a station on a fast line which has no platform at that particular station then for the purposes of the RG you have passed through that station.

You may have planned a journey and decided you are not double backing because of this, but what if you are diverted on to the slow lines that do have platforms? - Your journey would now be invalid.
 

WelshBluebird

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I don't want to hijack the thread, but in order for it to be doubling back, do you have to actually pass through the station again? Or would ending your journey there count as it?

A bad example I know, because the route is actually valid. But travelling Cardiff Central to Oldfield park, you can change at Bath Spa. As you pass through Oldfield Park on the way to Bath Spa, would arriving at Oldfield Park from Bath Spa constitute doubling back? If so, I would guess there is an easement which is why it is valid, if it isn't doubling back, then I guess that answers my question.
 

exile

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If you travel through a station on a fast line which has no platform at that particular station then for the purposes of the RG you have passed through that station.

You may have planned a journey and decided you are not double backing because of this, but what if you are diverted on to the slow lines that do have platforms? - Your journey would now be invalid.

That doesn't apply to Carnforth..... there is no way for a main line train to go through the slow platforms, they're on the branch (to Barrow) only. If the no double back rule was applied here it would be impossible to go from, say, Oxenholme to Arnside....
 

wintonian

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I don't want to hijack the thread, but in order for it to be doubling back, do you have to actually pass through the station again? Or would ending your journey there count as it?

A bad example I know, because the route is actually valid. But travelling Cardiff Central to Oldfield park, you can change at Bath Spa. As you pass through Oldfield Park on the way to Bath Spa, would arriving at Oldfield Park from Bath Spa constitute doubling back? If so, I would guess there is an easement which is why it is valid, if it isn't doubling back, then I guess that answers my question.

It would be double backing if in order to reach the destination on the ticket from the origin on the ticket you needed to pass through the same station twice (except group stations for interchange purposes, direct trains and the shortest route +/- 3 miles), stopping short at the station doesn’t bypass this requirement.
 

VTPreston_Tez

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I don't get why Leyland and Wolverton are annoying? I dont really get the rule can someone explain in simple terms?
 

WelshBluebird

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It would be double backing if in order to reach the destination on the ticket from the origin on the ticket you needed to pass through the same station twice (except group stations for interchange purposes, direct trains and the shortest route +/- 3 miles), stopping short at the station doesn’t bypass this requirement.

Sorry I don't think I was clear.
Oldfield Park is the station just before Bath Spa when coming from Cardiff.
However hardly any trains from Cardiff Central stop at Oldfield Park. So its either a change at Bristol Temple Meads / Filton Abby Wood or a change a Bath Spa.

I know via Bath Spa is a valid route. However, I'd guess it possibly could be counted as doubling back. As to do it, you need to pass through Oldfield Park initially when travelling into Bath Spa. And again then when going from Bath Spa to Oldfield Park. But you don't actually pass through Oldfield Park again, as that is where you alight.
 

lyndhurst25

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In other words the RG cannot be used to find valid routes if doubling back is an issue on the route you wish to find is or is not valid. You have to have an additional and map showing the topography of the rail network. Carnforth is an interesting case - if you pass through on the main line which has no platforms have you actually "passed through" the station or not?

Another problem is that the National Rail Timetable Map showing the whole of Great Britain doesn't show all the stations in certain areas (Leyland isn't on it for example). You instead have to refer to the local Liverpool/Leeds/Manchester/Sheffield map which is a diagram rather than a geographic map. On the local map diagram you can be forgiven for thinking that Leyland is NOT on the WCML. I'm sure there are other anomalies too. Can of worms just opened......
 

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yorkie

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I know via Bath Spa is a valid route.
Because it's no more than 3 miles longer, so valid on the shortest route rule.
However, I'd guess it possibly could be counted as doubling back
It is doubling-back. So not permitted when using mapped routes unless there is an easement.
As to do it, you need to pass through Oldfield Park initially when travelling into Bath Spa. And again then when going from Bath Spa to Oldfield Park.
Yes, that's doubling back.
But you don't actually pass through Oldfield Park again, as that is where you alight.
No, but it's still doubling back!
 

HowMuch?

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As the OP, can I just say that any discussion of how to define/find/use/avoid doubling back is defnitely NOT hijacking.
 

WelshBluebird

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Because it's no more than 3 miles longer, so valid on the shortest route rule.

It is doubling-back. So not permitted when using mapped routes unless there is an easement.

Yes, that's doubling back.

No, but it's still doubling back!

Thanks.
Nice to know why it is valid.
(I knew it was valid, but wasn't sure how it didn't run into the doubling back issue).
 

Skymonster

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So from the north, Luton via Luton Airport Parkway is doubling back but is valid because it is less than three miles...?

In which case why does there need to be an easement?

30255 Customers travelling via Wellingborough to or from Luton may doubleback via Luton Airport Parkway. This easement applies in both directions.

Andy
 

hairyhandedfool

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I don't want to hijack the thread, but in order for it to be doubling back, do you have to actually pass through the station again? Or would ending your journey there count as it?....

Depends where you define the end of the journey, if it is when walking out of the station, you have passed through it twice.
 

bignosemac

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and Bromsgrove-Bristol is permitted to double-back between Bromsgrove & Birmingham (easement).

Maybe. Although there are two priced flows for that journey. One 'Any Permitted' and one 'Not via Birmingham'.

You are then into the debate about whether the easement* trumps the route printed on the ticket. The routeing guide is silent on that.

*The easement says:

"300422 Customers travelling from Bromsgrove via Cheltenham Spa may travel via Birmingham New Street. This easement applies in both directions."


Does the double-back easement only apply to the 'Any Permitted', or should it apply to both routeings? If it does then why is there a 'Not via Birmingham' priced flow?

For the record I prefer to buy a ticket for this journey from or to a station where there is only an 'Any Permitted' priced flow. Big savings can still be made.
 
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hairyhandedfool

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A journey is only following a permitted route if the routeing on the ticket allows it (unless specifically mentioned in the easements).

When you check for the permitted routes of a ticket, you collect all routes for a 'Rte Any Permitted' ticket, then discard those that cannot be used by the routeing on the ticket. In the case of 'Rte Not Via Birmingham', all routes via Birmingham, including those allowed by an easement (unless noted otherwise), would be discarded.
 

John @ home

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When you check for the permitted routes of a ticket, you collect all routes for a 'Rte Any Permitted' ticket, then discard those that cannot be used by the routeing on the ticket. In the case of 'Rte Not Via Birmingham', all routes via Birmingham, including those allowed by an easement (unless noted otherwise), would be discarded.
I used to think this was the correct order in which to do things. It did seem the most obvious way to me.

But examination of the operation of the various booking engines suggests to me that they all calculate the Permitted Routes first, then apply any Route restriction printed on the ticket, and finally apply any positive or negative Easement. The effect of this seems to be that an Easement trumps everything else.

Whether this is the order in which things are meant to be calculated, I don't know. That order doesn't seem to be defined properly in the National Routeing Guide Data Feed Specification.
 
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