The mail train crashed into the GWR goods train, the engine of the LMS train clipping the edges of the two front-most goods vans of the GWR Train before crashing into the tender, which at that point was slightly askew of the main line as it was being shunted clear. The LMS engine crashed into the right-hand side of the GWR tender and derailed to the right, ploughing into two empty wagons of the up LMS train before it overturned onto its right side against the up slope near the bridge. The GWR tender was flung onto its left side against the north side of the bridge, while the GWR engine became wedged against the abutment, causing the first six vehicles (the parcel van, the other van, the front composite, the two 3rd class carriages and the rear composite) to become wedged under the bridge.