'Wrong line' working on the Cambrian?

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transmanche

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I had a trip on the Cambrian line down to Aberystwyth last week. On both the outward and return journeys, the trains passed each other on the right at the Talerddig passing loop - i.e. what would normally be considered the 'wrong' track.

Does anyone know why this is? Is it a regular thing?
 
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Gareth Marston

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I had a trip on the Cambrian line down to Aberystwyth last week. On both the outward and return journeys, the trains passed each other on the right at the Talerddig passing loop - i.e. what would normally be considered the 'wrong' track.

Does anyone know why this is? Is it a regular thing?

Yes it is since ERTMS was installed and also power operated points at Talerddig which replaced the 15mph air bag ones fitted with RETB. Standard procedure is for 1st train into loop to go into UP side regardless of direction of travel and let the 2nd service pass over the DOWN side at speed - presumably the cant of the track is better for the higher speed running that side.
 

louis97

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presumably the cant of the track is better for the higher speed running that side.

Most probably due to the up side being the 'loop', meaning the train would need to slow to diverge, where as this is not required going straight through the down side. Same applys at Chard Junction on the line between Exeter and Yeovil - apart from the down side is the loop.
 

louis97

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Same situation as Tisbury then.

Not quite, but similar. Tisbury loop only has signals at either end of the 'loop' line, so it is not possible to hold a train on the 'main' line, it will have to wait at the signal with the junction indicator for the loop or in the platform while the train it is going to pass goes into the loop - which can cause delay as a train will get a caution aspect at the repeater signal.
 

D1009

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It's actually not all that uncommon for trains to pass on the right hand side on single lines, I believe it is common practice on RETB lines in Scotland. The newly installed double track at Axminster is another example. There are many occasions like Chard Jn where there is a main line to be used by trains passing at speed and a loop to be used by the train that arives first.

A rarer situation is that between Ely station and Ely North Jn where there is a double track with both lines used on a regular basis in both directions, and trains scheduled to pass at speed on the right hand side.
 

swt_passenger

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There are varying reasons why though. At Axminster it is because the existing track geometry allowed for faster approach speeds to the station with RH running, because the single track sections either side are aligned on the RH side of the formation, and that gives the higher speed through the S&C.

This was effectively accidental, because that's how the line happened to have been singled. To provide for normal running, a few hundred yards more track slewing would have been needed at both ends of the dynamic loop.
 

DownSouth

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In Australia, where the majority of the interstate rail network is single track, it is generally the first train to arrive which takes the diverging route into the loop, regardless of which side is which. This is always the case for remote locations not linked to anywhere else by anything other than microwave transmissions, in these locations operation is by train orders and the points are controlled by the train crew.

In CTC (centralised traffic control) areas it is not uncommon for the first train to wait on the mainline if the trains are on track to arrive at roughly the same time. It's even possible for trains to pass each other without stopping, I saw this once at a country town while having a lunch stop on the opposite side of the highway - it was a loop for 1,800 metre trains with a ~1,400m freight train and a ~150m passenger train.
 

richw

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The loop at Penryn they also pass wrong side of each other due to layout of station

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LE Greys

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It's actually not all that uncommon for trains to pass on the right hand side on single lines, I believe it is common practice on RETB lines in Scotland. The newly installed double track at Axminster is another example. There are many occasions like Chard Jn where there is a main line to be used by trains passing at speed and a loop to be used by the train that arives first.

A rarer situation is that between Ely station and Ely North Jn where there is a double track with both lines used on a regular basis in both directions, and trains scheduled to pass at speed on the right hand side.

That's certainly the case. With island platforms, as on the West Highland, it makes sense for the driver to be on the platform side. Before RETB, it made tolken exchange easier as well, since many Scottish engines had tablet-catchers on the driver's side.
 

Tomnick

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I'd always understood that the right-hand running found nowadays on the West Highland lines only came about when RETB was introduced, to make it easier to access existing sidings. Taking Bridge of Orchy as an example, the existing layout (shown here, on one of John Hinson's excellent diagrams) clearly employs left-hand running, with trailing access to the sidings on the Up side. Following resignalling though, and with 9 points (and 11 at the other end) replaced (and relocated?) by hydro-pneumatic points, a change to right-hand running would make sense - otherwise you'd have to somehow hold over the points to make any movement into those sidings (and there'd be a great risk of a move stopping just clear of the points into the sidings - now operated from a ground frame - and setting back, forgetting about the sprung points that most of the train would have passed over).
 
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