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Max changes on the same line?
Let’s suppose you’re going from Reading to Hanwell. You might have to
make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? -- Ian ◎ |
Max changes on the same line?
Ian Clifton wrote:
Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? I assume doubling back isn't allowed, otherwise you could do that in one (changing at Paddington)? Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford. I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo |
Max changes on the same line?
In reply to this post from Theo to on 28 Mar 2019 at 16:52 ...
Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? I assume doubling back isn't allowed, otherwise you could do that in one (changing at Paddington)? Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford. I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Châtelet-Les-Halles. -- Richard J. (to email me, swap 'uk' and 'yon' in address) |
Max changes on the same line?
"Richard J." writes:
In reply to this post from Theo to on 28 Mar 2019 at 16:52 ... Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? I assume doubling back isn't allowed, otherwise you could do that in one (changing at Paddington)? Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford. I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Châtelet-Les-Halles. I think I intended something like Theo’s solution to be valid. But you’re right, in that calling my Passenger “sensible” is inadequate and probably misleading. A sensible person would probably make a longer or more expensive journey, rather than endure the faff of many changes. Maybe it’s better to make him an automaton: the Passenger always boards the very next train that gets him at all closer to the destination (even if a following train would get him closer still, or would reduce the subsequent changes required). -- Ian ◎ |
Max changes on the same line?
On 29/03/2019 00:48, Richard J. wrote:
In reply to this post from Theo to on* 28 Mar 2019 at 16:52 ... Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford.* I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Châtelet-Les-Halles. I read the original post as applying to journeys on a single line, not one where you change lines on the way. So if the only train you can catch at your local station doesn't stop where you want to get to, but there is a station where both trains stop, you have to change trains. As such, you should never need to change trains on the Underground short of a service problem on the District, Circle and Hammersmith and City lines, where they occasional change a Circle line train to H&S, stopping short. (Probably not the only place it can happen, but it caught me out recently, and ignoring the length where the Picadilly and District lines run on parallel tracks, but share some stations. I count those as different lines.) -- Tciao for Now! John. |
Max changes on the same line?
Ian Clifton wrote:
"Richard J." writes: A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Châtelet-Les-Halles. Apologies, I think I misremembered a change. (Also, I have a feeling there are through trains from Bourg to northern FR/BE/NL in the winter, which might skew things somewhat) I think I intended something like Theo’s solution to be valid. But you’re right, in that calling my Passenger “sensible” is inadequate and probably misleading. A sensible person would probably make a longer or more expensive journey, rather than endure the faff of many changes. Maybe it’s better to make him an automaton: the Passenger always boards the very next train that gets him at all closer to the destination (even if a following train would get him closer still, or would reduce the subsequent changes required). That would make it quite sensitive to time of day and service pattern, which would make the challenge rather fragile. Freedom to pick any train on a given day might make sense - the traveller can start at 00.01 and take any combination of trains that gets them there by closedown the next morning. But they can't wait for the one through train a week. Or you could look at trains with a regular service pattern - perhaps the last train is an all-stations stopper, but during the daytime you'd have to change. The next question is whether the passenger must travel on the same line as the through train, or whether they can take an alternative route (in my example, you'd probably have to use the around-Paris HSL rather than going into Gare de Lyon). I'd suggest the station should be one passed through by the through train, but they passenger need not take the same route to get there. (So for Inverness to Finsbury Park the traveller could change at Stevenage and take the Hertford Loop). Theo |
Max changes on the same line?
John Williamson writes:
On 29/03/2019 00:48, Richard J. wrote: In reply to this post from Theo to on* 28 Mar 2019 at 16:52 ... Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford.* I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Châtelet-Les-Halles. I read the original post as applying to journeys on a single line, not one where you change lines on the way. Yes, that’s what I meant, at first. This all came from a genuine journey I was planning (Oxford to Hanwell), I came up with the two‐change journey myself and then decided to see what Network Rail’s Journey Planner made of it. I thought the Journey Planner would always come up with a boring but “sensible” one change plan, and was slightly surprised when it came up with the double change plan too (only for certain departure times, of course). I then began to wonder if a higher number of changes could ever be required, and thought this might happen where several different services (partly) share the same route. But I’m struggling to make the conditions of the puzzle really concrete. [...] -- Ian ◎ |
Max changes on the same line?
In message , at 16:48:32 on Fri, 29 Mar
2019, Ian Clifton remarked: I’m struggling to make the conditions of the puzzle really concrete. I'm tempted to say "don't you just love it when civilians try to be policy wonks". But the question as posed was almost tightly enough drawn nevertheless. My own reservations were only about whether doubling back (thus requiring perhaps specialised ticketing) was allowed as part of the challenge, as well as enforced overnight - or even longer - layovers. For example, Denton to Reddish South, which until recently took a week with two double-backs, if we stick to the "on the same line" rule. -- Roland Perry |
Max changes on the same line?
On Fri, 29 Mar 2019 16:48:32 +0000, Ian Clifton
wrote: John Williamson writes: On 29/03/2019 00:48, Richard J. wrote: In reply to this post from Theo to on* 28 Mar 2019 at 16:52 ... Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford.* I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Chtelet-Les-Halles. I read the original post as applying to journeys on a single line, not one where you change lines on the way. Yes, thats what I meant, at first. This all came from a genuine journey I was planning (Oxford to Hanwell), I came up with the two?change journey myself and then decided to see what Network Rails Journey Planner made of it. I thought the Journey Planner would always come up with a boring but sensible one change plan, and was slightly surprised when it came up with the double change plan too (only for certain departure times, of course). I then began to wonder if a higher number of changes could ever be required, and thought this might happen where several different services (partly) share the same route. But Im struggling to make the conditions of the puzzle really concrete. [...] I had a look at my line, the Chiltern. Possible journey Brum Moor Street to one of the stations between South Ruislip and Wembley. The timetable sites insisted that I go beyond my destination and double back at either Wembley or Marylebone. I decided I could not be bothered to look up detail timetables - sorry to be so idle. Guy Gorton |
Max changes on the same line?
On 30/03/2019 12:51, Guy Gorton wrote:
I had a look at my line, the Chiltern. Possible journey Brum Moor Street to one of the stations between South Ruislip and Wembley. The timetable sites insisted that I go beyond my destination and double back at either Wembley or Marylebone. I decided I could not be bothered to look up detail timetables - sorry to be so idle. So the timetable sites refuse to give the cheapest route... not good! -- Basil Jet - Current favourite song... Spratleys Japs - Hands (Marc Riley session) https://www.youtube.com/watch?v=PTFmVrE1WAc |
Max changes on the same line?
In message , at 14:19:35 on Sat, 30 Mar
2019, Basil Jet remarked: On 30/03/2019 12:51, Guy Gorton wrote: I had a look at my line, the Chiltern. Possible journey Brum Moor Street to one of the stations between South Ruislip and Wembley. The timetable sites insisted that I go beyond my destination and double back at either Wembley or Marylebone. I decided I could not be bothered to look up detail timetables - sorry to be so idle. So the timetable sites refuse to give the cheapest route... not good! Not an issue I see here. One change at Gerrards Cross or High Wycombe, and nowhere near Marylebone. -- Roland Perry |
Max changes on the same line?
John Williamson wrote:
On 29/03/2019 00:48, Richard J. wrote: In reply to this post from Theo to on* 28 Mar 2019 at 16:52 ... Travelling on a Sunday in the winter, try Bourg St Maurice to Stratford International. I make 5 changes: Bourg St Maurice - Moutiers-Salins-Bride-les-Bains - Paris Gare de Lyon - Chatelet les Halles - Paris Gare du Nord - Ashford/Ebbsfleet International - Stratford International (on weekdays the ski train stops at Ashford.* I don't know if there are direct trains from Moutiers to Lille in the winter which would cut the changes to 3) Theo A "sensible & perfectly informed passenger" would know that you can get from Gare de Lyon to Gare du Nord by RER D without the need to change at Châtelet-Les-Halles. I read the original post as applying to journeys on a single line, not one where you change lines on the way. So if the only train you can catch at your local station doesn't stop where you want to get to, but there is a station where both trains stop, you have to change trains. As such, you should never need to change trains on the Underground short of a service problem on the District, Circle and Hammersmith and City lines, where they occasional change a Circle line train to H&S, stopping short. (Probably not the only place it can happen, but it caught me out recently, and ignoring the length where the Picadilly and District lines run on parallel tracks, but share some stations. I count those as different lines.) What about the Metropolitan line, that has Fast, Semi-fast and All-stops services? So, for example, if you board a fast train from Chalfont, wanting to travel to Nothwick Park, you'd need to change to a stopper ar Harrow-on-the-Hill. |
Max changes on the same line?
Ian Clifton wrote:
Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Robin |
Max changes on the same line?
In message , at 20:57:41 on Mon, 1 Apr 2019,
bob remarked: Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Apart from there being a regular service from York to Stevenage, meaning two changes eminently possible. Journey planners also offer the occasional one-change, at Kings Cross. Which goes back to my earlier question about how challenges like this interact with doubling-back. Sun-Fri Shippea Hill to Ely[1], for example, always requires doubling back; but still results in only two changes. [1] And of course anywhere further east on that line, *to* Shippea Hill. -- Roland Perry |
Max changes on the same line?
Roland Perry wrote:
In message , at 20:57:41 on Mon, 1 Apr 2019, bob remarked: Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Apart from there being a regular service from York to Stevenage, meaning two changes eminently possible. I obviously didn’t do my timetable checking properly, but I think the concept is clear enough: Stevenage has a limited set of stations north of Peterborough that are directly served, and Welwyn North has no direct service to Peterborough, so pick a station up the ECML not served from Stevenage with a station beyond not served directly by either Stevenage or Peterborough, but where direct Anglo-Scottish services pass directly through. Journey planners also offer the occasional one-change, at Kings Cross. Which goes back to my earlier question about how challenges like this interact with doubling-back. Doubling back makes finding examples much harder. Robin |
Max changes on the same line?
In message , at 19:01:22 on Tue, 2 Apr 2019,
bob remarked: Roland Perry wrote: In message , at 20:57:41 on Mon, 1 Apr 2019, bob remarked: Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Apart from there being a regular service from York to Stevenage, meaning two changes eminently possible. I obviously didn’t do my timetable checking properly, but I think the concept is clear enough: Stevenage has a limited set of stations north of Peterborough that are directly served, and Welwyn North has no direct service to Peterborough, so pick a station up the ECML not served from Stevenage with a station beyond not served directly by either Stevenage or Peterborough, but where direct Anglo-Scottish services pass directly through. That only produces a fairly long list of 2-change scenarios. I think we ought to be aiming for 3+ Journey planners also offer the occasional one-change, at Kings Cross. Which goes back to my earlier question about how challenges like this interact with doubling-back. Doubling back makes finding examples much harder. I'm wondering that (if allowed as a strategy) we might find circumstances where it 'adds one' to the list. -- Roland Perry |
Max changes on the same line?
Roland Perry wrote:
In message , at 19:01:22 on Tue, 2 Apr 2019, bob remarked: Roland Perry wrote: In message , at 20:57:41 on Mon, 1 Apr 2019, bob remarked: Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Apart from there being a regular service from York to Stevenage, meaning two changes eminently possible. I obviously didn’t do my timetable checking properly, but I think the concept is clear enough: Stevenage has a limited set of stations north of Peterborough that are directly served, and Welwyn North has no direct service to Peterborough, so pick a station up the ECML not served from Stevenage with a station beyond not served directly by either Stevenage or Peterborough, but where direct Anglo-Scottish services pass directly through. That only produces a fairly long list of 2-change scenarios. I think we ought to be aiming for 3+ It appears I overlooked the one per day each way King’s Cross - Aberdeen services that call at Stevenage, I’d been working on the assumption all Stevenage trains were Yorkshire only, that would make Stevenage - Newcastle or Edinburgh impossible without a change. That would have made stations north of Newcastle only served by Northern into 3 changers. Thinking a little further afield, start with the Eurostar Amsterdam service. This calls at StP, Brussels, Rotterdam Centraal and Amsterdam Centraal. Take Stratford International and Rotterdam Zuid, both of which the Eurostar passes through. Disallowing doubling back, the best I can figure is Stratford International - Ebbsfleet - Brussels Midi - Breda - Dordrecht - Rotterdam Zuid. From what I can tell this is possible to do without deviating from the route followed by the through train, and doesn’t involve spurious extra changes other than those needed to avoid doubling back. Robin |
Max changes on the same line?
bob wrote:
Roland Perry wrote: In message , at 19:01:22 on Tue, 2 Apr 2019, bob remarked: Roland Perry wrote: In message , at 20:57:41 on Mon, 1 Apr 2019, bob remarked: Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Apart from there being a regular service from York to Stevenage, meaning two changes eminently possible. I obviously didn’t do my timetable checking properly, but I think the concept is clear enough: Stevenage has a limited set of stations north of Peterborough that are directly served, and Welwyn North has no direct service to Peterborough, so pick a station up the ECML not served from Stevenage with a station beyond not served directly by either Stevenage or Peterborough, but where direct Anglo-Scottish services pass directly through. That only produces a fairly long list of 2-change scenarios. I think we ought to be aiming for 3+ It appears I overlooked the one per day each way King’s Cross - Aberdeen services that call at Stevenage, I’d been working on the assumption all Stevenage trains were Yorkshire only, that would make Stevenage - Newcastle or Edinburgh impossible without a change. That would have made stations north of Newcastle only served by Northern into 3 changers. Thinking a little further afield, start with the Eurostar Amsterdam service. This calls at StP, Brussels, Rotterdam Centraal and Amsterdam Centraal. Take Stratford International and Rotterdam Zuid, both of which the Eurostar passes through. Disallowing doubling back, the best I can figure is Stratford International - Ebbsfleet - Brussels Midi - Breda - Dordrecht - Rotterdam Zuid. From what I can tell this is possible to do without deviating from the route followed by the through train, and doesn’t involve spurious extra changes other than those needed to avoid doubling back. Looking at a map, it looks like the HS line that Eurostar uses skirts the edges of Breda and Dordrecht bypassing the stations themselves, but without deviating into those two places, there is no method of avoiding doubling back. Robin |
Max changes on the same line?
In message , at 21:58:43 on Tue, 2 Apr 2019,
bob remarked: Roland Perry wrote: In message , at 19:01:22 on Tue, 2 Apr 2019, bob remarked: Roland Perry wrote: In message , at 20:57:41 on Mon, 1 Apr 2019, bob remarked: Ian Clifton wrote: Let’s suppose you’re going from Reading to Hanwell. You might have to make as many as 2 changes (at Slough, and Hayes & Harlington), to reach a station you’d simply pass through if you didn’t change. What’s the most such changes a (sensible & perfectly informed) passenger ever has to make? How about something like Thirsk - York - Peterborough - Stevenage - Welwyn North? Apart from there being a regular service from York to Stevenage, meaning two changes eminently possible. I obviously didn’t do my timetable checking properly, but I think the concept is clear enough: Stevenage has a limited set of stations north of Peterborough that are directly served, and Welwyn North has no direct service to Peterborough, so pick a station up the ECML not served from Stevenage with a station beyond not served directly by either Stevenage or Peterborough, but where direct Anglo-Scottish services pass directly through. That only produces a fairly long list of 2-change scenarios. I think we ought to be aiming for 3+ It appears I overlooked the one per day each way King’s Cross - Aberdeen services that call at Stevenage, There's several Edinburgh services which call at both Newcastle and Stevenage. I’d been working on the assumption all Stevenage trains were Yorkshire only, that would make Stevenage - Newcastle or Edinburgh impossible without a change. That would have made stations north of Newcastle only served by Northern into 3 changers. If most pairs of LNER stations have at least one direct service between them per day, then we'll struggle to find any 3-change journeys on the ECML. Thinking a little further afield, start with the Eurostar Amsterdam service. This calls at StP, Brussels, Rotterdam Centraal and Amsterdam Centraal. Take Stratford International and Rotterdam Zuid, both of which the Eurostar passes through. Disallowing doubling back, the best I can figure is Stratford International - Ebbsfleet - Brussels Midi - Breda - Dordrecht - Rotterdam Zuid. From what I can tell this is possible to do without deviating from the route followed by the through train, and doesn’t involve spurious extra changes other than those needed to avoid doubling back. South of France E* must be another to look at. -- Roland Perry |
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