OSL S & T testing, contracted to Colas Rail, completed the signalling testing work at Bathampton Junction on the 30th August 2015 after a planned Temporary Period of Disruption of 6 weeks for the relaying works to be undertaken.

Bathampton Junction is situated at 104m 55ch on the Swindon to Bristol line ELR MLN1 and is the junction with the Trowbridge line ELR BFB. The area is controlled from Bristol Panel Signal Box, via an interlocking at Bathampton which dates from the 1970’s. The control panel is of a switch and exit button style with 40mm individual tiles controlling mainly three aspect signalling in this area. There was no alteration to the controlling signal box during this scheme

The project covered the relaying of 880B, 881A&B, 882, 883A&B, 884 and 885A&B points in the Bathampton Junction Area which were a mixture of HPSS and Clamp Locks, with In-bearer Clamp Locks and mechanical back drives under IMT Project Renewals. 880A points which were a HW machine was converted to Rail Point Clamp Lock operation. All points with the exception of 880A&B were fitted with a supplementary detector. The track was also lowered to accommodate future electrification.

A new PIL (Point Interface Location) was installed for each point ID and these were function tested off site by licensed OSL testing staff at the Unipart depot n Crewe prior to transporting to site.

On site pre-testing was undertaken in the 10 day period prior to the signalling disconnections being carried out on Thursday 06thAugust and again in the 3 day period prior to the commencement of the commissioning period from 25th to 30th August

Alterations were undertaken within the Relay Room housing Bathampton Interlocking, which is a Western Region E10K free wired Interlocking, and also in the existing locations B27, Y1, Y2, Y3, Y3/1, Y4, Y4/1, Y4/1B, Y4/1C & Y6. A new location case, Y4/1D, was provided required to house the circuitry required for an additional OSS+ which was added to B79 signal. Altered track circuits throughout the relaying were predominantly medium voltage DC with Five Western Region Quick Release tracks being altered, and two U Type Aster tracks, XH on the Up Main & XK on the Down Main.

Track circuit XH was an Aster U type/SF15 feed end which abutted a medium voltage DC track circuit feed XJ. As this is a prohibited combination for new works, this arrangement was rectified by fitting an EBI Frequency D Transmitter to XH, hybridising this track. As this was a non standard set up and no Testing Specification existed for testing this type of track circuit a new Testing Specification was written by OSL Testing Staff and submitted to Network Rail for acceptance on this scheme. Track circuits XI, XL and XT were fitted with stainless steel strips which are prohibited on points with a speed greater than 25mph. These track circuits, along with track circuit XJ, were fitted with a route stick 15 second timer as anti-bob protection. The timers were fitted into the respective (UP) and (DN) ULSR’s within the interlocking.

Ground signal B502 was removed and repositioned after relaying. Gantry signals B79, B179 & B477 required to be re sighted due to significant track lowering.

TPWS equipment was removed from the 4 foot at the start of the commissioning blockade and replaced and fully tested at commissioning. The existing OSS(1) for B79 signal was re-positioned to accommodate the spacing for the new OSS(2) fitment.

All signage in the affected area was removed clear of the worksite and either replaced or renewed according to the revised Signalling Scheme Plan and verified to sighting forms on commissioning. At the time of commissioning one bonding modification needed to be designed. This resulted in one signalling route in the reverse direction off the Trowbridge line being temporarily signed out of use and 880 points being clipped and scotched in the Normal positon. This modification has since been produced and was commissioned in a 6 hour possession on weekend of 17/18 October. All signalling is now restored to full operation.

This work was completed on time and in budget.