Loadings, cancellations and other issues

[whole diary]

[bobm]

It was an unusual failure.

The heating jammed on in the cab and could not be turned off.  It must have been bad to prevent the service going forward to Swindon.  The return journey would, of course, use the other cab and I assume the heating controls are different for each end.

Hopefully taxis were provided for those planning to use the 20:12.

[bobm]

Tonight's 18:32 Westbury to Swindon and 20:12 return cancelled again this evening.  Different unit from yesterday but again the cab heater is stuck on.

[grahame]

Tonight's 18:32 Westbury to Swindon and 20:12 return cancelled again this evening.  Different unit from yesterday but again the cab heater is stuck on.

Jeeze!   Same driver??

[grahame]

Tonight ... Cancelled

16:15 Westbury to Swindon due 17:03
17:36 Swindon to Westbury due 18:21
18:32 Westbury to Swindon due 19:23
20:12 Swindon to Westbury due 20:55

[bobm]

At around 17:05 the two later trains were re-instated.

Not a cab heater fault this time, but a sickly engine.

[bobm]

Severe delay on the 18:32 Westbury to Swindon tonight due to "congestion at Westbury".

Left 37 minutes late and currently 54 late between Chippenham and Swindon.  Should arrive just in time to work the 20:12 return working.  (It is also just a few minutes ahead of the 19:32 from Westbury....)

[John R]

Indeed. Travelling in the other direction the 1852 from SWI^» (Swindon - next trains) left just as the 1830 to Taunton arrived, thus denying passengers from east of Swindon their connection.  So the HST^▸ (High Speed Train) trundled slowly into Chippenham losing about 5 mins in the process. And then we waited whilst the 1852 was held at Thingley Jn for a late running HST from Castle Cary to come off the branch, losing a further 10 mins in the process, thus 15 mins delay and several pax needing taxis according to the TM^‡(resolve). All could have been avoided if the 1830 had been given priority on leaving Swindon.  (Oh, and the following PAD^» (Paddington (London) - next trains) to BRI^» (Bristol Temple Meads - next trains), also lost 9 mins because of the hold up.)

By the time the 1852 was ready to enter the branch to head south, the 1832 was more or less waiting at the other end.  So it was held at Bradford Jn which duly resulted in delays to 3 further trains heading towards Bath Spa.

Of course, the day was unusual in terms of traffic on the TW branch, but it does show how not having the facility to hold a train off the main line can cause considerable delays.

[bobm]

Indeed it has been an usual few days for traffic on the TW.

We have discussed it before - but it isn't always a case of waiting for a train to come off the single line in the opposite direction which causes hold ups.  A diverted HST^▸ (High Speed Train) I was on yesterday from Westbury was held at Bradford Junction for nearly 10 minutes while we waited for the Melksham train in front to clear Thingley Junction.

By the time we reached Thingley we were then behind another HST, which in turn was following the slower running 153.

An intermediate signal on the branch would help matters.

[grahame]

If things are running as planned, then the capacity of the Transwilts is enough to get around 36 trains through during a day - lets say 16 x HST^▸ (High Speed Train), 16 x 15x and 4 x freight.  Been done on a diversion day before, with nothing more that 4 or 5 minutes late.  But it's hard to timetable, and liable to blow up in someone's face if anything turns up more than a few minutes after it should.

Without full redoubling, double junctions at Thingley and Bradford, with sufficient space to allow a train to wait for the single line or wait for a mainline gap without blocking the main line / blocking the branch would be helpful.  But I think double junctions are out of favour and in effect would be designed as  a passing loop just on the branch?

An intermediate signal would cut the headway from around 16 minutes to 9 between trains - but would all trains then need to slow down in case the had to stop in the middle / it would need to be done 3 aspect from the ends.

More radically, why hold up that HST at Trowbridge - why not use the wasted 10 minutes to add Melksham and Chippenham stops as well as the Trowbridge one ...

No solutions, just ideas.  Now that we've proven that a service is useful, we can suggest  that these things that may be needed for toughening are looked at and - at the least - protected.

[John R]

An intermediate signal would cut the headway from around 16 minutes to 9 between trains - but would all trains then need to slow down in case the had to stop in the middle / it would need to be done 3 aspect from the ends.

Couldn't you just have a colour light distant?

[Network SouthEast]

An intermediate signal would cut the headway from around 16 minutes to 9 between trains - but would all trains then need to slow down in case the had to stop in the middle / it would need to be done 3 aspect from the ends.

You could have a two aspect stop signal in the middle, there'd be a two aspect distant signal in front of it (as John R says). So no need to slow trains down on a clear run.

If a distant signal shows a green, then the stop signal will also show a green.
If a distant signal shows a yellow, then the stop signal will show a red (unless it then clears to a green once the train has passed the distant signal).

Does that make sense?

[bobm]

Are there rules about the maximum distance between a distant and a main signal?

On the basis you can't have two trains heading in opposite directions on the single line, the only time an intermediate signal is going to be at danger is if a train is already heading away from a following train in the same direction.  You could therefore have the junction signal showing a single yellow at the entrance to the single line instead of the current green.

There are already distants on the single line for the junction signals.



The junction signal for Thingley is SN11 and, top right, you can see the distant - marked 11R.  The route has been set for a train to come off the single line as a train to Bristol has just cleared the junction.

[John R]

Are there rules about the maximum distance between a distant and a main signal?

On the basis you can't have two trains heading in opposite directions on the single line, the only time an intermediate signal is going to be at danger is if a train is already heading away from a following train in the same direction.  You could therefore have the junction signal showing a single yellow at the entrance to the single line instead of the current green.

I would have thought that would run the risk of the driver forgetting given the length of time before he/she encounters the intermediate signal (which is I suspect what you are thinking about). And it wouldn't really be a distant but a third aspect as the signal protects its own section. All a distant signal does is give an indication of the next signal ahead as Network SouthEast has described.

With mechanical signalling it's more intuitive as they are a different colour, but to the casual observer one colour light signal looks much like another.

Am I right in thinking that the bidirectional signalling on the main line between Bristol and Swindon via Box uses distants rather than three aspect working?

[grahame]

Playing "catchup" and putting these logs here rather than in public as there are metrics that could lead to the identification of individuals

2nd July, 15:14 from Swindon
11 from Swindon
-1 +9 at Chippenham
-6 +2 at Melksham
-7 +0 at Trowbridge
21/8
I have some interesting notes / metrics ...
153368
2 cycles CPM^» (Chippenham - next trains) to TRO^» (Trowbridge - next trains)
5 schoolchildren (2 with the cycles)
One topless chap, and two who looked like train spotters
Couple of blokes talking about upcoming court case they / mates are in
Report of lovely countryside and nice breeze in the train
No ticket checks / TM^‡(resolve) not seen.

10th July, 06:12 from Swindon
7 from Swindon
-1 +2 at Chippenham
-1 +6 at Melksham
-6 +13 and a bike at Trowbridge
14/7

Last night / 9th July ... times at Melksham
15:53 +6 -4 -> 25  29/10
16:30 +4 -5, 18 thru 27/9
18:03 +4 -12 -> 52 64/16
18:48 +2 -3 -> 9 12/5
19:18 +4 -6, 26 thru 36/10
I was at the station primarily to recruit walkers for the carnical parade on saturday / at least ensure that regular commuters knew about it and can join us if they wish, so the numbers on / through are counted as best I could and may not be exact - there may have been babes, people in loo, etc, that I missed.  I had hoped to count the later trains too, but an admin task on the forum dealing with a post that was alledged to be "inaccurate, outdated and defamatory. I believe that [the post] is now also unlawful, in breach of Data Protection Laws" had to be dealt with ...

[grahame]

09:48 Westbury to Swindon due 10:34
This train has been delayed at Trowbridge, will be further delayed at Swindon and is expected to be 9 minutes late.
This train will be diverted between Trowbridge and Chippenham.
This train will no longer call at Melksham.
This is due to signalling problems.