Railway infrastructure that does not appear to make sense to a 'layman'

[rgwwfc]

Recently a failed class 66 was holed up in the civil engineers siding at high wycombe and (assuming it was a total failure and not able to limp) this would have required two rescue locos to get around the reversal into the bay platform and then out to the mainline, assuming again that the recovery came from and left in the direction of London.

i'm thinking also of the central line connection to the chiltern line at west ruislip where the flow of traffic of lul stock moves goes north requiring a double reversal into the head shunt and back out across all running lines.

in both cases the connection to mainline would, seemingly, make more sense in the other direction. The obvious answer is the protection afforded to the mainline but is this not the point of catch points as in other loops and sidings?

maybe not that interesting to anyone else but maybe there are other cases on the network where people just ask why?

 

[61653 HTAFC]

The track layout at Dewsbury probably qualifies. The view from the platforms shows that there is space for two through tracks between the platform tracks, though only one is in place. When the Trans-Pennine Route Upgrade was in the planning/speculation stage, it would often be suggested on here that the second through track be reinstated to increase capacity. I've even got chatting to "normals" while waiting for a delayed TPE who have said there ought to be a second fast track through the station...

The problem that a layperson or non-enthusiast wouldn't necessarily pick up on, is that the current non-platform track is in the down direction, but is adjacent to the up line which serves platform 2 towards Huddersfield and Manchester. The vacant space is between the down main (not platformed) and the down loop serving platform 1 towards Leeds. Adding a "fast" up line would mean shifting the down main track over towards platform 1, and placing the new up main where the current down main is. This in turn would mean that the tracks for non-stopping trains in both directions would be poorly aligned for the viaduct in the Leeds direction, and the embankment and bridges over Huddersfield Road in the Manchester direction. You'd either need to rebuild the approaches on both sides of the station (never gonna happen) or you'd be forcing your "fast" services in both directions to make a dogleg either side of the station. This would of course significantly slow these services down, which is the exact opposite of what the route upgrade is intended to do.

 

[66701GBRF]

Infrastructure can change/reduce over decades. What might not make sense now probably did (or was different) years ago.

 

[zwk500]

in both cases the connection to mainline would, seemingly, make more sense in the other direction. The obvious answer is the protection afforded to the mainline but is this not the point of catch points as in other loops and sidings?

The railway for obvious reasons has always relied on multiple layers of protection, and if there is only minimal demand for the points then arranging them in a trailing fashion is safer than having them face the primary direction of travel even if it means shunting in is a pain.

maybe not that interesting to anyone else but maybe there are other cases on the network where people just ask why?

There's a couple of bay platforms (e.g. Taunton and Wolverhampton) that are only accessible to empty movements, meaning all trains wanting to depart from them must terminate in another platform and shunt over. As mentioned, lots of 'awkward' layouts date from earlier times when capacity was not so precious so additional shunts were less of a concern.

 

[30907]

Recently a failed class 66 was holed up in the civil engineers siding at high wycombe and (assuming it was a total failure and not able to limp) this would have required two rescue locos to get around the reversal into the bay platform and then out to the mainline, assuming again that the recovery came from and left in the direction of London.

Pedantically, you only need one loco as it can run round .on the main lines.
As the CE siding you mention is clearly on or parallel to the old formation of the Maidenhead line, I suspect the layout is a hangover from the 60s. Does it ever house a lengthy train, or just failures, tampers etc?

i'm thinking also of the central line connection to the chiltern line at west ruislip where the flow of traffic of lul stock moves goes north requiring a double reversal into the head shunt and back out across all running lines.

Not sure - that does look odd.

in both cases the connection to mainline would, seemingly, make more sense in the other direction. The obvious answer is the protection afforded to the mainline but is this not the point of catch points as in other loops and sidings?

Yes, but trap points cost money, so if you can avoid them... and points on the main running line also take more of a hammering so that's extra cost too.

 

[Chris Butler]

The railway for obvious reasons has always relied on multiple layers of protection, and if there is only minimal demand for the points then arranging them in a trailing fashion is safer than having them face the primary direction of travel even if it means shunting in is a pain.

There's a couple of bay platforms (e.g. Taunton and Wolverhampton) that are only accessible to empty movements, meaning all trains wanting to depart from them must terminate in another platform and shunt over. As mentioned, lots of 'awkward' layouts date from earlier times when capacity was not so precious so additional shunts were less of a concern.

Can you wxplain more about Taunton (I live there) ? Why is there this restriction ? Which platform ? The restriction is only for arrivals ?

 

[JonathanH]

Can you wxplain more about Taunton (I live there) ? Why is there this restriction ? Which platform ? The restriction is only for arrivals ?

Platform 6, the bay platform on the up side at Taunton, can only be accessed by 'reversing' into it using a shunt movement. Therefore it can only be used for departures.

 

[30907]

Can you wxplain more about Taunton (I live there) ? Why is there this restriction ? Which platform ? The restriction is only for arrivals ?

The Up side at Taunton, and specifically P6, cannot be accessed from the Cogload direction as there is no facing crossover. So a terminating train has to use the Down side and shunt across to P6 if it needs to clear the line.

 

[HamworthyGoods]

Bays such as at Taunton and Huntingdon where you can only depart were historically to save providing facing point locks.

The train would arrive and terminate in another platform and then shunt into the bay to stable before departure, in many cases the loco would need to run round the train first which it couldn’t do in a bay anyway.

 

[edwin_m]

The safety aversion to facing points doesn't really apply these days - point machines include the lock as standard so there's no extra cost from that, so if a facing point is operationally better and doesn't cost a lot more, it is likely one will be provided.

Another reason for points leading to sidings to be trailing is so a locomotive can propel wagons into the siding and leave them there, without getting trapped between the wagons and the buffer stop.