TRUST (SDR) entries on Realtimetrains

[AdamWW]

Can anyone help me with something that's puzzling me?

Looking at Realtimetrains for the Coryton Line (Heath Junction to Coryton), I can see that once a train has passed Heath Junction onto the line there are no times shown as train describer entries.

Some trains produce GPS reports up the line, some don't.

When there's no GPS, often there will be an arrival and departure time shown at Coryton (sometimes appearing a while after the train actually left) labelled as TRUST (SDR). It seems that these are manual entries.

So far so good.

But there seem to be two types of SDR entry.

One is when the train actually makes it to Coryton, and the times seem plausible. Checking a few shows that they are also shown on Recenttraintimes.

The other type appears (I think) when a train is actually turned round at Ty Glas but there's no cancellation message that Realtimetrains shows. There, the entries just seem to mimic the delay from the final (inbound to Coryton) or first (outbound) entry with the result that often the train is shown as leaving before it arrived. These don't (for the few I checked) show on Recenttraintimes.

I don't imagine that Realtimetrains is making stuff up, and neither do I suppose that anyone is deliberately entering false data.

I appreciate I'm using third party web sites and nothing is official, but they are presumably using official open data feeds and I'm curious as to what's going on.

 

[louis97]

But there seem to be two types of SDR entry.

SDR is a manual report entered by the signaller, as such they can put what they want. There isn't two types (unless you want to consider reporting an arrival, departure and pass as different types).

These don't (for the few I checked) show on Recenttraintimes.

They don't appear on Recenttraintimes because the train will be cancelled after the fact. You might be able to look back on them on Realtime Trains and see they now show cancelled and you cannot see the SDR reports that did not make sense. Although I'm not sure on the time frame that it will pick up said cancellations.

Also worth mentioning that, sometimes SDR reports are just plain wrong and don't make sense. That is just the nature of the beast, we're all human and mistakes happen. Some get corrected by Delay Attribution, they'll says "TRUST DA".

 

[AdamWW]

SDR is a manual report entered by the signaller, as such they can put what they want. There isn't two types (unless you want to consider reporting an arrival, departure and pass as different types).

There certainly seem to be two types in the sense of how they are applied in this case. Not the same as two actual types, I'm sure.

They don't appear on Recenttraintimes because the train will be cancelled after the fact. You might be able to look back on them on Realtime Trains and see they now show cancelled and you cannot see the SDR reports that did not make sense. Although I'm not sure on the time frame that it will pick up said cancellations.

Ah OK. Realtimetrains doesn't seem to amend them later, unless it's days later.
So it seems that Recenttraintimes is picking up information that realtimetrains either doesn't get or doesn't use.

Also worth mentioning that, sometimes SDR reports are just plain wrong and don't make sense. That is just the nature of the beast, we're all human and mistakes happen. Some get corrected by Delay Attribution, they'll says "TRUST DA".

Fair enough. But this seems to be fairly consistent (albeit I've only looked over a few days).

It seems that for trains that never made it to Coryton, somebody or something is putting in bogus times at Coryton, and ones that don't make sense.

Now so long as whatever is showing the results overrides them as recenttraintimes seems to, I can see that no harm is done, and perhaps this is just exposing the perils of allowing open access to the data then letting ignorant people like me attempt to interpret the results. But I'd be curious as to why they are being put there in the first place because it's a bit confusing when trying to work out how much of a mess things are in.

Anyway thanks for that - most informative.

== Doublepost prevention - post automatically merged: 16 Jan 2025 ==

Ah actually...

Just looked again at recenttraintimes for one of the ones where realtimetrains shows a TRUST (SDR) entry and recenttraintimes doesn't show anything, and seen that recenttraintimes doesn't actually mention the partial cancellation whereas it does for one where realtimetrains also says the train was cancelled.

So now I'm still confused.

 

[louis97]

Ah OK. Realtimetrains doesn't seem to amend them later, unless it's days later.
So it seems that Recenttraintimes is picking up information that realtimetrains either doesn't get or doesn't use.

It could be overnight, I don't think it would be days later. However as I said I am not sure what the cut off is for Realtime Trains using this data.

It seems that for trains that never made it to Coryton, somebody or something is putting in bogus times at Coryton, and ones that don't make sense.

Now so long as whatever is showing the results overrides them as recenttraintimes seems to, I can see that no harm is done, and perhaps this is just exposing the perils of allowing open access to the data then letting ignorant people like me attempt to interpret the results. But I'd be curious as to why they are being put there in the first place because it's a bit confusing when trying to work out how much of a mess things are in.

One reason they get put in could be to remove them from a train 'line up' on TRUST. This shows all the trains at a location and if a train is yet to arrive or depart it will remain in the list until it is either cancelled or an arrival or departure report is made at that location or at one of the next locations in the schedule. It seems a little bit odd that anyone would have a 'line up' for Coryton however. You typically don't see this on passenger trains anyway, normally its on shunt moves that don't end up running at a station, a fake departure report is put in to remove the train from the list.

 

[AdamWW]

It could be overnight, I don't think it would be days later. However as I said I am not sure what the cut off is for Realtime Trains using this data.

One reason they get put in could be to remove them from a train 'line up' on TRUST. This shows all the trains at a location and if a train is yet to arrive or depart it will remain in the list until it is either cancelled or an arrival or departure report is made at that location or at one of the next locations in the schedule. It seems a little bit odd that anyone would have a 'line up' for Coryton however. You typically don't see this on passenger trains anyway, normally its on shunt moves that don't end up running at a station, a fake departure report is put in to remove the train from the list.

In this case there would always be a train describer entry once it reaches Heath Junction.