GEORGE LAW LTD, Building and Civil Engineering

Bridgnorth Wheel Drop

Case Study - Bridgnorth Wheel Drop (1) - 200

Severn Valley Railway
ICE Minor Works 3rd Edition
June 2010

Case Study - Bridgnorth Wheel Drop (2) - 200

Back in 2009, when one of the Severn Valley Railway’s (SVR) most prized locomotives had to travel to another historic railway for urgent maintenance work, it became clear that SVR had a real need for its own wheel drop facility.  The lifting jacks at Bridgnorth, the only real practical alternative are invariably occupied for extended periods with locomotives undergoing major overhaul.

Case Study - Bridgnorth Wheel Drop (3) - 200

A disused wheel drop assembly was identified at Leicester Midland MPD and purchased with the plan to relocate it to the SVR’s Bridgnorth MPD.  The wheel drop was found to be in good working order even though the gears and motors date back to 1952.  George Law Ltd, SVR’s construction partner on the £3.5m ‘Highley Engine House’ and £2.4m ‘Repair of Failed Slopes and Reinstatement of Railway’ projects were tasked to undertake the relocating works.

Case Study - Bridgnorth Wheel Drop (4) - 200

The first phase of the project was to dismantle the wheel drop equipment from its existing location and to survey its housing pit so a duplicate could be constructed at Bridgnorth.  Whilst the first phase was underway, the new site underwent preparation works which included the realignment of a water main which passed right through the most ideal site at Bridgnorth.

Case Study - Bridgnorth Wheel Drop (5) - 200

Once the drawings were in place for the new housing pit, work commenced on the excavation within the MPD building.  The challenging parts of this phase were the confines of the building and the need to keep open an emergency route through the building, as maintenance to locomotives continued around the site.  40 concrete piles were used to curtain the excavation area and a 6m deep hole was created with the last few feet being dug by hand due to the restrictions of site space preventing the use of a higher capacity machine.

With the excavation of a (l)6m x (w)5m x (d)6m hole complete, the next phase was to construct the housing pit utilising three concrete wall pours to create different levels for steel work.  Provisions were made for power cables, water pipes and drainage pump, access panels and recesses for pit lighting.  Then additional pours were used to create eight concrete plinths.  With circa 200m3 of concrete now in place, the installation of the wheel drop equipment could commence and although a complex task, it was carried out virtually trouble free, due to prior planning and surveying of the Leicestershire site.  As the steel work was moved into place, it was cleaned and painted to give a neat and tidy appearance.

The final phase of the project is to connect the new wheel drop to the existing external rail lines and to replace all ‘broken out’ concrete to create a single level floor slab incorporating two other maintenance lines into the building.  The end result is that SVR now have a much needed facility which will not only improve maintenance schedules at Bridgnorth, but is capable of providing valuable income from outside contract work.