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The Raised Track Refurbishment



PART 1

Despite manful attempts to re-sleeper the track over the last 18 months a number of concerns had arisen about odd derailments occurring.


Investigation uncovered the fact the track had become gauge widened in some places and tight in-gauge in others. Study of the rails themselves showed considerable wear on the two outer rails due to the carriages always running on them and one rail being common to both 3½" and 5" gauges,


Over the last 2/3 months the raised track team have considered the possibility of replacing the track but retaining the existing mushroom post and beam track bed. Experiments were conducted on procedures to clean up the trackbed and then putting a screed on top. 
A spare beam section was used as a test bed. The beam top was power wire brushed and then painted with a bonding agent, a precisely measured screed mix of cement and bonding agent was then laid between shuttering on top of the bed. The shuttering being carefully arranged to give camber where necessary. This has been allowed to weather and has shown to be well bonded. 


Consideration had to be made as to what track steel could be found, the current bull-head section appeared to be no longer available. Also another concern, over the years, has been carriage stability when passengers board the carriage in the station or lean out on the curves to take photographs. The anti-tipping rail did provide the necessary safety aspect.

It was thought sensible to run the carriages at 7¼" gauge, for stability, and retain, independent of these, the other two gauge’s rails. This configuration requires 5 rails instead of the current 3. The rails themselves to be from 25 x 10mm mild steel welded to 40 x 8mm flat mild steel sleepers at 12" centres.

A 6 foot section of this configuration was constructed and presented for discussion in October at a Thornton Hough meeting, this met with general approval. Distortion due to welding has been avoided by adopting a strict welding procedure. The full rail assembly will be mounted on recycled 50 x 25 mm plastic sleepers, thus avoiding the wood rot over time. 

Sunday running ceased at the end of October and efforts were immediately directed to stripping the swing bridge (down to its column) and some 30 ft of track each side. These sections of track are retained as templates for rolling/fabricating the new 3 metre track panels. The swing bridge will have a 12mm thick steel plate deck, with abutments at each side to match and enabling positive track locking arrangements to be made. The anti-tip rail will be reinstated as construction progresses. 

Steel for approx. one third of the track is ordered which has generated a tremendous storage headache resulting in clearing the end of the shed and fabricating a tubular rack to receive the materials.


The whole project may take up to 3 years but the usual summertime running is planned to be possible by fitting transition sections at the ends of the new track. When the complete track is finished the steaming bays will be modified where necessary as will the track inside the bunker. The carriages will require new axles and modifications to suit the wider gauge after track completion.

Now we have taken the plunge we have to get on with it and hope for fair weather and willing volunteers!!

Words & Images Alan Pennell


 


Part 2

18th January 2016;

Latest from the raised track, first curved section for the turn table completed, trimmed and fitted.
Just needs drilling and bolting to the turntable.

31st January 2016;
A good day, two curve sections and two 10 foot straights welded plus ten anti-tip rail supports.
Three teams working, the welders, the track layers and the painters .
Track temporarily laid on the beams to fit all of the plastic sleepers. 

& 31st March 2016

Words by Allan Powell, Images by Allan Powell & Roger Couche
 


Part 3 (nearly there)

4th December 2016;
Men at work today.
Barry welding the final section of seven-and-a-quarter track to complete the raised track. 

and Len grinding off a previous weld.
(Images Peter Bolderson)


Test Run 27th April 2016

27th April 2016;

On the new section with vertical boilered De Winton. (Peter Bolderson)


Test Run 4th May 2016

Images Peter Bolderson


 


Raised Track Signals

Raised Track Signalling
The Signals! The Signals!
Dave McKaigue. 

The origins of the Raised Track Signalling System are lost in the mists of time but the people who put the system in, knew exactly what they were doing – ingenious and built to last is the appropriate description!

Unfortunately, the System was showing its age. Nature had taken advantage of the warm, dry cabinets in a way that would delight an Attenborough. Red and Green filters, distorted by the heat from the powerful filament lamps, had begun to melt and the breaks in the track, required to trigger the signals, were interfering with good running. Renewing the track made an upgrade to the signalling system, inevitable.

Cautiously removing the Red and Green plastic filters from the signal and then their reflectors revealed a daunting sight – a rat’s nest of wires. (The Rat had presumably moved out on the grounds that it was too untidy!). It was easy to pick out the two relays wired as a flip-flop but what immediately impressed was the thickness of the incoming wiring. This was Electrical Engineering on a robust scale! It took a while to sort out which wire went where and what it did.

Wildlife Reserve & Rats Nest


Almost by accident, the signal upgrade fell into two phases. In the first phase we replaced the filament lamps with the new generation of ultra-bright LEDs. In the second phase, the triggering system was modernised.

It is only recently that ultra-bright Green LEDs have become available. At this point we worried that even ultra-bright LEDs might not be bright enough in sunlight. In the great tradition of the original engineers, we over-engineered the brightness to the point where there have been comments about the need for sun glasses! Our main headache was that the original filament lamps drew 24 volts from a rough power supply in the bunker – a power supply rough enough to spike at 34 volts at times. To tame this power supply to something more manageable and well-behaved, we had to build a power unit to fit inside the signal cabinet. The LEDs were simply switched by a 24 volt relay connected to the Green Lampholder.

Temporary Circuit Board


Phase two set us worrying about how to trigger the signals. It was clear that the new track would be best unbroken in order to give it maximum strength and integrity. We experimented with a treadle system but unfortunately the front bogie of some of the smaller locomotives, derailed. Salvation came from an unexpected quarter. I was having a roller shutter door fitted to my garage. A light beam is used to stop the door if the threshold is obstructed. It is a robust and reliable system - ideal for detecting trains. The Light Beam System would require power and it was clear that a more robust power supply would be needed than that provided in Phase One.

It was this point that ambition and foolhardiness blossomed. What if we got rid of the relays and the rat’s nest? What if we replaced the relays with an electronic flip-flop?

It took great courage to remove the works from Signal 1. What if we couldn’t sort out the cables? Did we have sufficient understanding of the system? What if….it didn’t work? It was a point of no return.

The Contiboard backing fell to pieces like a degenerate Weetabix. We were left with a heap of relays, wires and lampholders at our feet. We installed the electronics and apprehensively, switched on. It worked! The following week, we installed a new printed circuit board with a few tweaks to make it belt, braces and gaffer-tape reliable. The Light Beam Trigger also worked a treat. If it proves to be as reliable as the original system we will be surprised and delighted.

New printed circuit board


Unfortunately, inside the Signal still looks like a Rat’s nest.

The work was carried out by Dave McKaigue and Peter Watts, with occasional assistance from other members as required. 

New Signal Working