The mystery of Preston Road

As has been well attested, there is/are no Arrivals data for Preston Road - either on the TFL API or the underlying Trackernet data. I understand that this is because there’s a signalling mismatch between Wembly Park and Harrow (all the data in that section is speculative at best).

And yet, if you go to Preston Road, there are arrivals boards which … work. So where are they getting the data from?

… and can we have it? Please?

@grahamwell If it’s anything like the end-of-lines like High Barnet: It’s in the “pdf timetables” and would need to be manually adjusted to direction to provide the platform numbers. At Barnet, for example, we extract the TransXChange data and add a manual “1-3” taken from Railway-Junction-Diagrams.pdf - Google Drive

Some of the Met stations don’t have their correct platform numbers for so they’ve got code to work out the direction and show a platform number ( Harrow-on-the-Hill, Rickmansworth, Chorleywood, and Amersham) for Chiltern Railways to match the TfL Met data!

I guess at terminals it’s OK, because the train timetables have penty of time for “recovery” and also there are usually many platforms for this to happen.

Those are useful links, thanks.

I’m not sure it gives an answer though. It seems as though there’s another system that provides arrivals data to the on-platform indicators. There’s a hint of this at other stations where the on-platform indicators don’t seem to agree with the TFL or trackernet data, but it’s a little difficult to nail that down. However Preston Road seems like a good example where there’s no data at all, yet the on-platform indicators seem to give reliable real-time information about arrivals.

How? Perhaps it is derived from timetable data but that wouldn’t be very accurate and the on-platform indicators seem pretty good. Maybe I’m being conspiratorial to think that there’s another system, but it does look like that.

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Hi @grahamwell - I believe that section is signalled by an old radio system. I’d have to check but I imagine that is powering the predictions coming out on the platform. This is the same signalling that was present in the Hammersmith branch of H&C/Circle line that existed prior to about 2018.

I know that it’s not been possible to hook this radio signalling into Trackernet in the past. The 4 Lines Modernisation project will resolve all of these issues with missing stations (as has happened with affected stations in the past).


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In addition to what @jamesevans says, the really annoying thing is that you can’t just use the previous and next station and use the printed timetable “Also calls at Northwick Park 2 mins and Preston Road 4 mins after Harrow-on-the-Hill.” because…

the station are skipped by “Fast and semi-fast trains peak hours only”!

I guess I we will have to wait for the 4LM period 9 to occur. !