Unique Rail Bridge Plagued by Failures Despite Extensive Works
Network Rail is grappling with "significant challenges" in maintaining the UK's only sliding railway drawbridge, the Vazon Bridge in Keadby, near Scunthorpe. Despite extensive, multimillion-pound maintenance works undertaken earlier this year, the unique structure has continued to suffer multiple recent failures, causing disruption for both rail and canal traffic.
The Vazon Bridge, which dates back to the 1860s and was converted into a sliding mechanism in 1925, allows trains on the rail network to cross the Stainforth & Keadby Canal. To permit boats to pass, the entire bridge deck slides open before returning to its original position for rail passage.
Last year, Network Rail, in collaboration with contractors AmcoGiffen and specialists 1stinrail, initiated two phases of significant repair work to enhance the bridge's reliability.
In February 2024, engineers undertook a complex operation to strengthen the canal’s north wall by installing a 24.5-tonne precast concrete slab and metal supports on the bridge deck. The rails were also renewed. Michael Clegg, Network Rail's route engineer for the Eastern region, explained that these structural improvements aimed to combat the "voided construction" of the historic abutment, which was not designed for modern rail traffic loads. This involved grouting, infilling voids, comprehensive brickwork refurbishment, and the installation of a reinforced capping beam for better load distribution.
Additional efforts were made to reduce vibrations, a common cause of equipment failure. "This included implementing a new directly fastened track system specifically engineered for this asset," Mr Clegg stated, adding that the bridge was re-levelled to create a smoother transition for trains.
The works themselves presented considerable difficulties. "The asset presented significant challenges due to its complex construction form and substantial size," Clegg admitted. Refurbishing abutments within the canal also required maintaining continuous water flow for a nearby power station's emergency cooling system, necessitating a "caisson solution" for safe access.
However, the bridge's troubles did not end there. In August 2024, sensors detected a fault in the sliding mechanism. It emerged that temporary metal plates, precision-welded to the running rails in February to compensate for a height discrepancy, had developed cracks and distorted. While quickly rectified, this caused temporary disruption for canal users.
Despite these meticulous efforts, the Vazon Bridge has continued to experience periodic breakdowns due to a mix of mechanical and structural issues, notably exacerbated by thermal expansion. This has led to mounting frustration among canal users, who possess a legal right of way but frequently find their passage blocked.
"Keadby bridge has experienced a range of challenges across multiple disciplines," Mr Clegg acknowledged. "Some issues stem from a maintenance perspective, particularly related to wear on the historic mechanical equipment. Other challenges involve the asset’s response to extreme heat conditions, which primarily affects structural expansion but also impacts the temporary running rails we installed."
The recent hot weather has been particularly problematic, with the bridge's sensors preventing operation when temperatures rise too high. A failure on May 31st saw the bridge stuck, with Network Rail promising a reopening by June 22nd. Shortly after, it became stuck in the open position, blocking canal traffic. Though quickly moved to a closed position for trains, it continues to block the canal.
Currently, Network Rail engineers are manually operating the bridge only in the mornings to allow canal users to pass, keeping it closed at other times. Automatic operation will only resume when ambient temperatures drop below 15°C. The monitoring intelligence has been improved, with girder temperature sensors now setting a threshold of 21°C, down from a previous ambient temperature threshold of 26°C.
Mr Clegg confirmed that these temperature thresholds are under active review to better balance rail and waterway traffic, especially given the bridge's role as a "critical freight corridor" for services like the DRAX power station.
Despite the ongoing frustrations, Mr Clegg highlighted clear successes from the recent works. "The structural abutment works have successfully halted any further settlement of the asset and the track works and realignment have significantly reduced vibration across the bridge," he stated. Furthermore, the installation of new sensors provides Network Rail with earlier information, enabling more proactive maintenance.
Network Rail expressed confidence that current works focusing on the rolling wheels and removing temporary plates will "eliminate key areas of vulnerability." However, Mr Clegg offered a realistic prognosis for the historic structure. "It’s important to acknowledge that this remains a historic moving structure subject to intensive maintenance requirements and temperature sensitivity," he said. "While we will continue to closely manage these factors to optimise performance, the inherent characteristics of this asset mean it cannot be made fully reliable in all conditions. We will always prioritise operating the asset safely within the boundaries defined by our engineering assessments."
I recall my previous post asking about it. It was sorted quickly but must have cost a lot with about 15 big taxis.
