...but only if the TPWS is working (both trackside and trainside), the brakes are fully effective, and there is sufficient traction.
There is also the edge-case scenario whereby the train could pass the TPWS grids at just the right speed to avoid setting off an overspeed intervention, but then accelerate for some reason before hitting the buffers.
And, yes, 507s aren't very sprightly, but if the train was doing 12.5mph at the loops, it could have reached perhaps 20mph by the buffers.
To be honest, I'm slightly surprised that at high-risk locations such as this, there isn't a second set of grids set to 5mph or so nearer the buffers.
Anyway, the RAIB investigation will reveal all in about 12 months' time...