B A S E D O N B R I M S C O M B E
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A crowded corner on the old layout, 2016.
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The same area, Brimscombe project, December 2020.
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Progress at Brimscombe A 'Hall' class 4-6-0 assisted by a large 'Prairie' gets stuck in on the climb to Sapperton with a Cheltenham-Paddington train. Assisting engines (coupled at the front of passenger trains on the Western Region) were attached at Stroud and detached at Kemble. Apart from a couple of through services, only local trains stopped at Brimscombe. Freight trains were assisted in the rear (but not coupled) after stopping at Brimscombe, the assisting engine dropping off at Sapperton Sidings before returning light engine. All Down freights (apart from fully fitted) stopped at Brimscombe to pick up wagon brakes which had been pinned down at Sapperton Sidings before descending the incline. Relatively overlooked is the fact that some Down freights were also assisted from Kemble - there being a steep incline to the east of Sapperton tunnel - the assisting engine being taken off at Brimscombe. Taking photos as work progresses is a great way of revealing errors not apparent to the unaided eye - noticeable here is the 'dog leg' near the crossover on the Down main, in need of a spot of tweaking. |
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With the main lines completed after two weekends of intensive tracklaying, by November 2018 the first train had run on the Down line. By the time of the LOGGIES (Luton O Gauge Group) visit in December both lines were available for running. A LOGGIES visit can always be relied on to produce a variety of interesting loco types, the December visit including the first 'Grange' and 28xx 2-8-0 to run over the new layout. Some of the visiting GW locos are seen in the photo (left). The layout has been wired up for conventional DC (analogue) operation, and wiring the yard was complicated by the fact that with all points 'normal' the yard is controlled from the small yard panel, but with the double slip and associated point on the main line 'reversed' the yard roads are powered from the Up controller, allowing trains to leave the yard or reverse into either the Up Loop or Goods Shed road. After a little head scratching, and a few false starts a relatively simple solution to the problem of wiring this up was suggested in an article by Stewart Hine in the November 1979 issue of Model Railways - click HERE to read more. |
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Back to basics
Conventional wisdom dictates that the 'juice' should be fed to points at the 'toe' end, but the two points in the yard are 'heel' fed, that is if the point lies 'normal' then the feed at the 'toe' end is connected to whichever road is clear. Switching is carried out by a combination of relays and the switches on the point motors which alter polarity of the crossing 'vee' ('frog'). To enable this the roads through the Goods Shed and into the Carriage Shoot are permanently connected to the Yard controller so always 'live'. Depending on which way the double slip is switched, control is either by the Yard or Up controller. The point at the other end of the yard is also 'heel fed'. From an operators point of view there are no complicated section switches, just throwing the points automatically switches power to the appropriate track. The yard (right) became fully operational in early September 2019 with points worked from a temporary panel at Brimscombe East (BRE) - in due course this will be replaced by a lever frame. One end of the double slip in the yard can also be worked from the goods yard panel so that shunting engines can make use of the carriage shoot road whilst running round. This is interlocked with and can be 'locked out' by the signalman at East 'box. |
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Point motors were also installed in the crossover by the engine shed and on the shed road. With the crossover 'normal', control of the Up and Down lines are under their respective controllers, but when 'reversed' the crossover and section of Down line within the station are worked from the Up controller. This enables returning banking engines and terminating auto-trains to cross from one line to the other. To get this working quickly it was temporarily wired using a relay board (left). Following a long period of use to check that the circuits were 'bomb proof', together with the loco shed spur point it was hard wired using a relay board and switching contacts on the Tortoise point motors. The circuitry was also used for the crossovers in the storage roads.
The points leading from the Down Loop onto the Down Main were next to be commissioned. With points normal the loop is isolated, but when reversed the loop is fed from the Down controller. However, at the station end of the loop the connection trails in from the Up Main via a diamond crossing. With the points here normal, the loop is isolated, but when reversed it is connected to the Up controller - trains normally being reversed into the loop under the Up controller. |
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In the rare event of a shunting move from the Down loop into the headshunt or coal siding, the points at the opposite end of the movement are reversed and the appropriate controller used - a slight inconvenience for what should be a very infrequent happening. Considering that there is an awful lot of temporary 'spaghetti' dangling under the benchwork, the layout works remarkably well - although a heavy duty common return bus has since been run underneath the benchwork all the way round the layout, about 120' of cable in all ! To avoid any potential confusion, once wired for the Up main, a further common return will then be run round for the Down line.
The LOGGIES paid a return visit in September, bringing with them a variety of locos and rolling stock including this elegant Lee Marsh 'Dean Goods' in pre-Grouping GWR livery, which made stately progress around Brimscombe. Two battery powered radio-controlled locomotives also made an appearance, one of which distinguished itself by becoming the first locomotive to 'officially' work through the as yet unpowered storage roads. |
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A job that I was certainly not looking forward to was installing the 24 point motors in the storage roads. A work station was set up on the workbench so that all wiring could be soldered onto the tags in comfort prior to fitting the motors. To aid identification when working under the staging, all 'commons' on the Up side are yellow, those on the Down side green. The operating crank also needed beefing up for 7mm points. Following a couple of weekend 'possessions' the laborious task of fitting the motors was finally complete. After testing, only a slight adjustment here and there was needed.
Having spent several weekends on my back under the layout, for ease of working all the wiring was then brought up to tagstrips fitted on top of the staging (left). This also makes for a convenient working height for us 'oldies' ! The crossovers at each end of the yard were then wired up allowing trains or assisting engines to leave the storage roads in the opposite direction to how they arrived. With the storage roads now semi-operable, it was with a feeling of quiet satisfaction that a variety of trains could now be worked from the storage roads and around the layout, as originally intended. |
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In fact four points still need their motors installed in the storage roads, although these will have to be offset as the baseboard framing is in the way. But with eight roads each capable of holding two trains, capacity is more than adequate for the time being. Two minor alterations at the SMX end of the storage roads involve the dead end roads. Two of these roads on each side of the main running lines have been extended to give a little more storage space for rolling stock (right). This will also compensate for the loss of the two outer dead end roads which are planned to become 'docks' for cassettes, so that visiting locomotives can be more easily placed on the layout without blocking or hindering trains already running on the main lines. Work was eventually completed during the period of the first Covid lock down in 2020, with final wiring to the lever frames and commissioning of St Mary's Crossing frame (below), and Brimscombe West (below right), not taking place until January 2021. Signalling remains to be installed at a later date. LL |
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SMX (St. Mary's Crossing)
No.1 SMX Up Distant (on Brimscombe Up Starter) No.2 SMX Up Home No.3 Points U1 (Entry to Up storage roads) No.4 Spare No.5 Points DX (Down crossover) No.6 Points D1 (Exit from Down storage roads/release Down Sidings 1-4) No.7 SMX Down Distant (on BRW Down Home) L/H rotary switch operates entry points for Up Nos.1-4 Sidings: Position 1 - Up No.1 Siding Position 2 - Up No.2 Siding Position 3 - Up No.3 Siding Position 4 - Up No.4 Siding R/H rotary switch operates exit points for Down Nos.1-4 Sdgs (Released by Lever No.6): Position 1 - Down No.1 Siding Position 2 - Down No.2 Siding Position 3 - Down No.3 Siding Position 4 - Down No.4 Siding |
BRW (Brimscombe West)
No.1 BRW Up Distant (on SMX Up Home) - lever not installed No.2 Points U1 (Exit from Up storage roads/release Up Sidings Nos.1-4) No.3 Points UX (Up crossover) No.4 BRW Down Loop Starter No.5 Points D2 (Entry to Down storage roads/release Down Sidings Nos.1-4) No.6 Points D1 (Exit from Down Loop) No.7 BRW Down Home No.8 BRW Down Distant (on BRE Down Starter) L/H rotary switch operates exit points for Up Nos.1-4 Sidings (Released by Lever No.2) Position 1 - Up No.1 Siding Position 2 - Up No.2 Siding Position 3 - Up No.3 Siding Position 4 - Up No.4 Siding R/H rotary switch operates entry points for Dn Nos.1-4 Sdgs: (Released by Lever No.5) Position 1 - Down No.1 Siding Position 2 - Down No.2 Siding Position 3 - Down No.3 Siding Position 4 - Down No.4 Siding |
© 2021 John E Emerson and not to be reproduced in any physical or electronic form without express written permission of the author.
B A S E D O N B R I M S C O M B E
B A S E D O N B R I M S C O M B E