NRG - Routing Guide - Greater Anglia - Mistley to Westerfield

[jpickardvs]

I asked a question last year about the routing guide rules and timetables (https://www.railforums.co.uk/thread...-ipswitch-to-mistley-and-harwich-town.288142/).

I didn't get the answer I was looking for, however now that I have more information from the start of this year, I'm going to answer the question differently.

If you download this map: https://www.greateranglia.co.uk/media/12286/download?inline, then you can see a rail line section between Ipswich and Mistley. The map legend (on that map) says that there are limited services on that leg. If there were indeed limited services on that leg, origin Ipswich destination Mistley, or vice versa Mistley to Ipswich, then Ipswich would be a valid single common routing point between Westerfield and Mistley (and vice versa).

However, the year 2025 summer timetables as they were last year, and the winter 2025/2026 timetables as they are this year, do not appear to incorporate any services whatsoever between Ipswich and Mistley (and vice versa). You can see this by checking the National Rail journey planner.

Focussing then on origin Mistley (in order to understand my challenge): the only way to get from Mistley to Ipswich is by changing at Manningtree. This in my mind should exclude Ipswich as a routing point. However, the stations data that we get from the routing guide stations file (RJRGnnnn.RGS) shows this:

MIS,IPS,MNG,,,

The format says "MIS" is the station identifier, "IPS" is the first related routeing point and "MNG" is the second related routing point.

So my question is around "IPS" - how can I try and discount IPS as a routing point/common routing point (if you look at travelling in both directions Mistley to Westerfield) so that the remaining valid routing point is MNG?

Thanks in advance.

 

[greaterangrier]

This seems a bit like an XY problem, similarly to the previous thread. You are asking how you can validate a route based on logic which doesn't appear to follow the Routeing Guide. See https://www.raildeliverygroup.com/our-services/essential-services/rail-data/routeing-guide-data.html for the eNRG specification which journey planners use.

the only way to get from Mistley to Ipswich is by changing at Manningtree. This in my mind should exclude Ipswich as a routing point.

The origin routeing point is MANNINGTREE only because it is the first routeing point related to Mistley encountered on this route (7.1.7).
You can get from Mistley to Ipswich direct: 07:45 Harwich International to Cambridge.
You can't exclude routeing points because of hunches/what's in your mind. Yes, it is pointless to have routeing points which are unreachable, but a special rule isn't needed to exclude them - the fact that there's no trains to a certain routeing point means journeys that way won't be validated anyway.

So my question is around "IPS" - how can I try and discount IPS as a routing point/common routing point (if you look at travelling in both directions Mistley to Westerfield) so that the remaining valid routing point is MNG?

XY problem.

Mistley to Ipswich via Manningtree (11.00mi) is valid because it is within 3 miles of the shortest route. The shortest route (10.48mi) can be calculated using the mileage data given in the routeing guide. See: 7.1.2, 7.1.3.

If you wanted to see all methods applied to attempt to validate the route:

Classify journey:
Are there common routeing points for Origin=Mistley and Destination=Ipswich?
Routeing Points: {Manningtree, Ipswich}, {Ipswich}.
Yes: Ipswich is common => Journey is "local".

Local journeys:
By 7.2.2, the journey is permitted if any of the following pass validation.
Method 1: Is this a direct train? No.
Method 2: Is the journey on a through train from MISTLEY to IPSWICH, then a through train from IPSWICH to IPSWICH? No.
Method 3: Is the journey the shortest route? No.
Method 4: Are there any stations on the route we are checking that are part of a station group? No. => Check irrelevant.
Method 5: Is the journey within 3 miles of the shortest route? Yes.
Method 6: Are there any doublebacks through Mistley or Ipswich? No. => Check irrelevant.

Method 5 passed. Route is valid.

So in summary:

• origin, common and destination routeing points are different
• origin routeing points aren't determined by elimination. The origin routeing point is the first routeing point related to the station encountered.

 

[jpickardvs]

Thank you everyone. I finally came to the solution I needed. Everyone who has replied has been of great help.