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Shelf Island

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Test Facilites




This description is rather dull, I want to get it over with now before I move on to the history and economy of the island, and then the railway.


I want a test track which will let me do more than run-in a new loco, and I have made a list of the parameters I can check. I am using a Hornby Mk3 coach as the gauging vehicle, so hopefully anything I can expect to want to run will fit through the layout. Back in the late 1970s someone told me BR took these coaches through the tunnel to Blaenau Ffestiniog for much the same reason.


1. Kadee coupler installation location - the c. 24-inch radius reverse curve

2. Kadee coupler alignment - the transition from level track to a 1:20 descent

3. Pickups on an 0-4-0 chassis - the Setrack point

4. Wagon free-running and weighting - the 1:30 descent to a level track

5. Controller feedback performance - the various gradients

6. Axle alignment - the transition from a 1:20 descent to an 18-inch radius curve

7. Loco starting torque and adhesion - 1:20 gradient

8. Compatibility with four track standards: Peco/Hornby Setrack, Peco code 75, 00-BF (much the same as the Peco) and 00-SF / HO-SF (but not DOGA Fine)


Having written this out, I have tried to make the transitions at the ends of gradients as gentle as I can, and the track work as flowing as possible within the space available. Section breaks are cuts into the rails made with a cut-off disc in a mini drill and then filled with an epoxy resin. I am trying to avoid track faults and to keep everything as good I can, for the sake of the layout to follow.


The geometry of curving track on a gradient is complex. Logically, the track should have a definite super-elevation, and this means a Y point on a gradient should be raised in the middle, with the crossing above the two stock rails. I have resisted this temptation, and made the point flat.


I worked out this list on the coach to Ally Pally (30th March 2015) and I expect I'll add to it - I'd welcome any comments on additional details I might be looking for. Since then I have added some more:


9. Wheel back to back dimensions - the 00-SF section

10. Vertical gauging below the railway bridge, especially for long vehicles which are straddling across from 1:20 section below the bridge to the level track beyond it - thank you Stu (Stubby 47)

11. Pivots of bogies and pony trucks - gradient transitions

12. Bogie vehicles bottoming-out on the transitions at the tops of gradients


- Richard.

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  • RMweb Gold

Possibly clearance under overhead track for any out of gauge loads ?


Isolation sections to hold locos ( unless DCC)

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  • RMweb Gold

Yes vertical clearances need some care. The original idea was for the track below the bridge to have a limited clearance and accept only small or modified locos like the 03 with the lowered cab height. As it happens, knowing the trains would cope well with 1:18 and building the track beds at 1:20, I've ended up with a quarter inch or so to spare below the bridge. But this slack will be eroded by a longer vehicle. The original plan had passenger trains formed by the 03 with a London Underground driving trailer (like Alderney), but the larger space might allow a bubble car or similar. The design of the bridge structure is in hand, the finished clearance will probably stay an unknown until I have it wedged into place.


Wiring is for DCC, but operation will be analogue (one train in steam) to begin with. I want operation to include an interchange of trains from one loco to another on the gradient below the bridge, and I think DCC is the best way to go for me.

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Nice list of test features there, a few not covered in the loop test track I'm building,

might just rework it a tiny bit to include them.


Look forward to seeing more.

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  • RMweb Gold

Thanks for this. I've spent an hour or so today with item 9 back to back dimensions. Consistently, every Bachmann loco was spot on, and every Hornby loco about 0.1 mm too tight for the 00-SF section.


- Richard.

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  • RMweb Gold

There is a twelfth item which I overlooked: bogie vehicles bottoming-out on the transitions at the tops of gradients. This never occurred to me, but my Hornby class 155 DMU does. I don't know why I bought this model - I think at the time I guessed it would be comparable to their 153 (which is excellent, but retooled), and it is not.


- Richard.

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