After successfully completing a 3.5-mile journey beneath the ground, HS2’s massive tunnel boring machine (TBM) Mary Ann has wrapped up her mission to carve out the first bore of the Bromford Tunnel, connecting North Warwickshire to Birmingham.
Now, the 1,600-tonne engineering marvel is being carefully dismantled in preparation for her next underground adventure.
The first major step in the disassembly process took place on Friday, 30th May 2025, when Mary Ann’s enormous 8.62-metre diameter cutterhead was hoisted into the Birmingham skyline. Weighing in at 120 tonnes, the cutterhead was lifted from the 22-metre-deep tunnel portal at Washwood Heath using a powerful 700-tonne crawler crane—an operation that took just 90 minutes.
Over the next three months, a dedicated team of 15 engineers will continue to dismantle the 125-metre-long machine at the Washwood Heath site. Once fully disassembled, Mary Ann will be returned to German manufacturer Herrenknecht, where she will be refurbished and modified to meet the demands of her next tunnelling assignment.
Mary Ann spent an impressive 652 days and nights underground, steadily excavating the first section of the Bromford Tunnel. Meanwhile, her sister machine, Elizabeth, is currently hard at work boring the second tunnel, with breakthrough expected later this year.
Image and video credits: HS2
