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Chinnor Independent Line (CIL) – Project Prima 2

A second batch of concrete sleepers was kindly donated by Network Rail in November 2023, a project we called 'Prima 2' – Princes Risborough Infrastructure Materials Acquisition. It yielded about another 140m of material.

This was handled quite differently from the previous batch now known as 'Prima 1', which had involved 6m track panels with bullhead rails too short to re-use. Prima 2 comprised 9m (30ft) flat-bottom railed concrete sleepered panels. The 30ft rails are considered long enough to be worth reusing, though we will need to buy a lot of fishplates and bolts. So why did we handle these panels so differently?

Our track relaying machine (TRM) is designed (by British Rail in the 1970s) to carry 60ft (18m) track panels using its twin crane jibs. The short Prima 1 panels had to be handled by just one jib using 4 'slings' (lifting straps), but two could therefore be carried at a time. To stop each load rotating on its hook and hitting the machine, we had to tie them off to the vehicle frame. This was all very time consuming and needed a lot of hands. The 9m Prima 2 panels could be picked up using the track clamps ('bales') which come with the TRM and carried stably between the two jibs with no slings or ropes (see picture). The panels can be accurately placed on the ground just by the operator manipulating the jibs and winches. Very much quicker, and far fewer people needed. Also the materials were travelling a much longer distance – from NR’s Whitemoor yard in Cambridgeshire – so for economy we needed high capacity lorries not carrying their own heavy cranes about.

So, a completely different plan was hatched. A hired crane was set up in the Chinnor yard gateway. 4 lorries each brought 4 track panels of about 5 tonnes each. The crane moved the panels off the first two lorries onto our sturgeon track carrying wagon, which was then towed to Thame Junction. Our TRM met it there and unloaded the 8 panels to stack them on the CIL trackbed. The wagon went back to Chinnor and was reloaded and the cycle repeated. The whole job was completed in just two days on 8th and 10th November.

Our Permanent Way department was busy through November into December laying flat bottom rail into sleepers laid out at the end of the Princes Risborough headshunt, the start of the CIL a while ago. We already had enough for about 90m of the extension. In January the work has continued, laying out some bullhead sleepers from the Prima 1 batch, and some rail from the old lifted track will be lifted in soon. This method is planned to reach round the tight curve as far as the industrial estate bridge.

A second team is working on the other side of the bridge using a different technique, setting up a production line in an assembly area to produce 60ft (18m) track panels from the Prima 1 components and some recovered rail, to then be carried to site (by the TRM) and laid as full panels.

Incidentally we’ve been asked why we have an old tyre hanging off each end of the TRM. It’s just a place to carry them. We sometimes rig them to act like fenders on a boat, when carrying a load close alongside; but if they were left on the sides we would collect platforms and gate posts along the way.

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