Mighty Morphin' DMUs on RTT (ref. BHM)

[Pigeon]

Poking around on realtimetrains (which I have recently discovered) I have found what looks like an inconsistency and I do not understand it.

1M07 from WOS terminates BHM platform 11b at 1644. The "Schedule Information" field has "WTT schedule UID P83409, identity 1M07; Runs SO between 26/05/2018 to 08/12/2018; Service code 22329000". The "Operational Information" field says "Pathed as Class 158 (Express Sprinter) DMU".

1V21 to HFD departs BHM platform 11b at 1650. The "Schedule Information" field has "WTT schedule UID P83427, identity 1V21; Runs SO between 26/05/2018 to 08/12/2018; Service code 22329000". The "Operational Information" field says "Pathed as Class 150/153/155/156 (Sprinter) DMU".

Looking at what goes on at BHM around those times, there is nothing else, either in service or ECS, using platform 11 between 1V12, which comes in one end and goes out the other, and 1M07/1V21. The only stock to have arrived and remained at platform 11b before 1V21 departs is the terminating 1M07; and with only 6 minutes to do it in, it doesn't seem possible that one lot of stock can go out ECS and another lot come in and RTT just doesn't show it because it's too trivial or something. Therefore, the two services must be composed of the identical vehicles.

So how is it that 1M07 is "Pathed as Class 158", and 1V21 is "Pathed as Class 150/153/155/156"?

And then the same thing happens in reverse at HFD - 1V21's stock is sitting in platform 1 waiting to go back out as 2C71, then there is a twangy noise and a puff of coloured smoke, and it turns back into a 158. I don't understand this either.

 

[bb21]

These are timing loads, not booked traction.

There is no reason why two services formed by the same stock cannot have differing timing loads. "Pathed as 158" simply means "timed for max 90mph (and able to use sprinter differentials)", and "pathed as 150, etc" means "timed for max 75mph (and able to use sprinter differentials)".

Put a 158 on it will easily keep to time on all services operated. Put a 150 on instead it may lose time on services "pathed as 158".

 

[Starmill]

The 'class 158' timing load in question is actually for 100mph, not 90.

That tells you all you need to know about the meaningfulness of that to the allocation.

The reality is that those services are probably worked by a Turbostar anyway. It could be in combination with a sprinter for all or part of that time, though.

 

[bb21]

The 'class 158' timing load in question is actually for 100mph, not 90.

That tells you all you need to know about the meaningfulness of that to the allocation.

The reality is that those services are probably worked by a Turbostar anyway. It could be in combination with a sprinter for all or part of that time, though.

Err, yes. That sounds more gibberish-like than I thought.

Only if our 158s did 100mph...

 

[Pigeon]

These are timing loads, not booked traction.

There is no reason why two services formed by the same stock cannot have differing timing loads. "Pathed as 158" simply means "timed for max 90mph (and able to use sprinter differentials)", and "pathed as 150, etc" means "timed for max 75mph (and able to use sprinter differentials)".

Put a 158 on it will easily keep to time on all services operated. Put a 150 on instead it may lose time on services "pathed as 158".

Oh, OK. Thanks very much, that makes it all make sense!

 

[causton]

Can we have a popup that comes up whenever anyone types 'Pathed as' or 'Timing Load' explaining this for the almost daily posts like this we get

 

[The Planner]

And also one that the timing loads we use do not always feed identically down to RTT etc, they will be timed as 170s on our side, or 168s on Chiltern as often gets asked.

 

[yorkie]

Can we have a popup that comes up whenever anyone types 'Pathed as' or 'Timing Load' explaining this for the almost daily posts like this we get

I recommend @Pigeon has a read of this post by an experienced train planner: https://www.railforums.co.uk/threads/1k20-1542-manchester-piccadilly-to-hull.82004/#post-1422088

 

[Pigeon]

Yes, thank you, that was interesting too.

If questions like this are common, it suggests that it isn't so much a case of this site needing a popup, but of RTT needing a "Glossary" page that explains what all the various terms and abbreviations they use signify. I looked for such a page before posting this thread, but I couldn't find anything. It is after all a pretty arcane and obscure subset of railway knowledge, and the existence of sites like RTT is exposing it to people who haven't encountered all the specific terminology in general pre-internet conversation even if they do have enough interest in railways to go poking through diagrams and the like.