NR Signs Off ‘One of a Kind’ Bridge Makeover

A mammoth nine-day programme of engineering work on the UK’s only sliding canal bridge in Keadby, near Scunthorpe, has been completed by Network Rail engineers, HBPW, AmcoGiffen and their supply chain.

Working round the clock between midnight on Saturday 17 February and the early hours of Monday 26 February, more than 100 engineers worked tirelessly to strengthen one of the canal’s walls and improve track equipment.

HBPW Partner, Jon Livesey, who was at site with Principal Engineer, Ross Hardy, said: “It has been a long journey but we now have a great outcome.

“Keadby Canal Bridge, also known as Vazon Railway Bridge, was built as a swing bridge in 1850 to carry the railway over the canal.  The bridge was later converted to a drawbridge in 1925 by Sir William Arrol and the deck and much of the operating equipment was then replaced in 2003.

“However, there had been numerous faults leading to difficulties in opening & closing the bridge, closures of the railway and canal and repeated repairs and inspections. All resulted in disruption on a vital freight route between Doncaster and Scunthorpe.
 
“To date we’ve spent over two and a half years on the scheme, initially designing some temporary repairs after a significant failure and then building on the work undertaken by others, to understand the causes behind the problems so that we could develop a robust solution.”

The eventual solution put in place during last month’s possession, included the installation of a 24.5 tonne steel and pre-cast concrete beam on the canal’s north wall, in order to strengthen it.

And as Jon explains, HBPW’s temporary works were key to the operation’s overall success.
 
“The section of wall suffering the most damage was removed and reinstated with a more robust beam to support the bearings. The aim was to dissipate shock loadings that result from wheels crossing the gap in the rails and, by doing so, reduce future damage to the canal’s masonry walls.

However, to carry out this work, engineers had to lower the canal wall but first had to drain part of the Stainforth and Keadby canal using a limpet dam, a structure positioned on the side of the canal wall to create a water-tight seal, so that the water level could be locally lowered enabling teams to carry out the vital repairs.
 
“Initially we had considered a cofferdam but the implications for the adjacent power station were too great. They have a licence to extract water from the canal, hence the decision to take the limpet dam route,” added Jon.
 
In addition to work on the canal wall, existing timber waybeams, used to support the track, were also replaced.
 
“Permanent way maintenance teams had always had problems keeping base plate screws tightened so we used the possession as an opportunity to change the system to one featuring steel rail bearers with Vipa and Vanguard base plates. These have previously been used to great success on the Selby and Goole swing bridges so, using them at Keadby, was the logical solution.” he added. 

New rails covered in a special coating and painted white, have also been installed so that they absorb less heat in summer, reducing expansion.

“We work very closely with PBH Rail and they provided us with the track design, using the same people who had been involved with the design of a similar system in use on Selby Swing Bridge, so they were able to bring that experience and knowledge to the table.

“The change to the permanent way has increased the weight of the bridge, so we have now brought in specialist assistance from one of our partners, Fairfield Engineering Solutions, to check that the mechanical and hydraulic systems have sufficient capacity for the additional load.” 

Further work will be undertaken to adjust the running gear that opens and closes the bridge to even out the loads on it.

“It’s been a very busy time for me and my team.” added Jon “In addition to the work at Keadby Drawbridge we’ve also provided the designs to Network Rail’s Works Delivery Team for an extensive waybeam renewal at the nearby King George V bridge as part of the same blockade.”
Sean Ellerby, Scheme Project Manager for Network Rail, said: “These vital upgrades will improve reliability and deliver smoother journeys for passenger and freight services for years to come and, by replacing old with new, will result in less maintenance-related disruption.

“Carrying out this work over nine continuous days (was) more efficient and meant less disruption to services than access on multiple weekends and I would like to thank passengers and freight users for their patience and understanding while the work was carried out.”

Ben Brooks, Capital Delivery Director at Network Rail, said on Linked In: “Working with a temporary limpet dam, AmcoGiffen (were able to) upgrade one of the bridge abutments to ensure Keadby continues to carry heavy loads for years to come.

“All p-way componentry (has been) upgraded too whilst the railway (was) closed to traffic, maximising the benefit of the blockade.

“There was great evidence of collaborative team work on site and some useful conversations around how we deliver the best possible project outcomes with (both) operations and maintenance colleagues and public pedestrian users in mind.