Passing loops at stations - design criteria

[whole diary]

[grahame]

Is the loop at Penryn big enough for the NMT to pass the other unit running on the branch?

I was chewing the cudd this afternoon and talking about passing places at single track stations where there's passenger and significant non-passenger traffic.

Firstly, if you're only never passing two passenger trains, only a passenger and a freight or perhaps two freights, do you need two platforms?   I recall reading about a station at The Mound with just one platform, but is it current practise anywhere / is it still allowed?  ((Georgemas Junction??))

Second question - does the loop need to be long enough for both trains, or just for the shorter train?

[LiskeardRich]

Penryn is one very long platform, although I think called 1 & 2. The loop starts at Truro end and returns to the single line around half way along the platform. So no footbridge needed etc

[John R]

You don't need two platforms if you are sure that there aren't going to be two passenger trains passing (or to be more precise two trains which both need to call at the station).

The loop could in theory be just long enough for the shorter train (with I'm guessing a bit of an overlap).  Though if you are thinking of Melksham then I guess it would be very short sighted not to have a loop long enough for a diverted express service.

Where it does become a problem is if the freight train isn't able to start off immediately. Then it will still extend beyond the length of the loop and the passenger train would not be able to start.  Similarly, a non-stop express service would have to stop in the platform and wait for the freight to move on, so not ideal.

[eightf48544]

Highly on the Severn Valley has one platform and a quite long goods loop.

In Germany there are a number of stations like Penryn where there is now only a single extended  platform with the loop starting halfway instead of two platforms one either side. The Rostock to Wismar line via Bad Doberan has many. Thus passengers for either direction don't have to cross the line. The major difference with Penryn is that the trains stop facing each other rather than one train passing the other before it stops.

[grahame]

Some interesting thought and feedback.   Apart from the freight loop on the Severn Valley Railway, are there any such loops  remaining on the main network where freight and passenger trains pass with just a single passenger platform that's bidirectional?  If not, is that because of current rules or simply because there'e no call?

Thank you for reminding me of Penryn, which also reminded me that a loop just away from a station allows trains to pass and both to call, all be it at the operational cost of needing to allow time for the passing and extra wear and tear on stopping and starting trains.

[The Tall Controller]

Apart from the freight loop on the Severn Valley Railway, are there any such loops  remaining on the main network where freight and passenger trains pass with just a single passenger platform that's bidirectional?  If not, is that because of current rules or simply because there'e no call?

Dunbar

[Rhydgaled]

Some interesting thought and feedback.   Apart from the freight loop on the Severn Valley Railway, are there any such loops  remaining on the main network where freight and passenger trains pass with just a single passenger platform that's bidirectional?  If not, is that because of current rules or simply because there'e no call?

Most (all?) passenger services use just one platform (which is bidirectional) at Haverfordwest, but the rails through the other platform aren't completely rusted, which suggests that something uses them from time to time. Do the oil trains use it to pass passenger services?

Also, but not quite what you are asking, Dovey Junction has one long platform split into A and B sections, with a loop around one half, allowing passenger trains to pass and call in both directions.

[eightf48544]

Dunbar is a single bidirectional platform on a loop off the EC double track  mainline so down stopping trains have to cross the Up line twice.

Malton has a single platform on a double track line. Trains to York have to cross the Scarborough bound line twice, non stopping trains don't have to cross as it's double track through the station.

Forres and Keith both seem to have a single bidirectional platform with a  loop outside the platform.

Also in Scotland Ladybank seems to be a case of rationalisation of track gone mad. It is the junction between the Perth and Dundee lines from Edinburgh. The Perth Line being single track and the Dundee line double. The Perth line joins by a single lead junction onto the Dundee direction line and serves only that platform in both directions. Thus that platform serves 3 destinations Perth, Dundee and Edinburgh whilst the other platform only serves trains from Dundee to Edinburgh. Just to confuse the issue there is a loop north of the junction on the Perth line.

Dore is another station that originally had 2,  maybe 4 platforms two on the Hope Valley and two on the Chesterfield line? The Chesterfield platforms (if they existed)  were closed many years ago.  The Hope Valley line has been was singled and is served by one platform  which is bidirectional. This was to save repairing the footbridge. It's now a bottle neck

Source Track Atlas Of Mainland Britain Platform 5 2nd edition.

[Red Squirrel]

Highly on the Severn Valley has one platform and a quite long goods loop.

...and there are occasions when two trains are booked to cross there that both call at the station. Bit of a rigmorole, but it can be done with a bit of shunting.

[eightf48544]

Just remembered HSB crosses three trains at Schierke on the way to the Brocken. It's  to allow  service train up the mountain. to pass a slower special also going up the mountain whilst crossing the service train down the mountain.

Quite easy Special goes into Down loop following service train goes into up loop. Special backs out of down loop. Down service train comes into down loop. Up service train departs, special comes into Up loop and Down train departs, special follows service train up the mountain. Due to the top of the line being a spiral you sometimes see the service train on the higher level