Wouldn't rule it out, but would be extremely surprised. From the images I've seen:
- The middle pier and the southern pier are showing signs of damage and significant displacement, but no displacement is visible beneath the rail line, and the bases of the piers appear to be in the correct position, this makes any subsiding/settlement of the foundations of the pier unlikely.
- the worst affected pier by some distance is the middle pier, the southern pier is less damaged, and from the photo I saw the northern pier is relatively intact. This makes this being caused by a landslide on either side of the bridge unlikely, to twist it in the way it has been at the middle support, for the northern pier to be intact the southern pier would have to continue the twist, and would have to have sustained far more visible damage.
- I would be very surprised if the bridge was anchored into the ground to the point the ground moved and took anchor with it, managing to rip two other supports from their footing. The bridge looks like its designed for the majoity of the load to be taken by the supports, I wouldn't even be surprised if it was only resting on the ground to either side so it could better resist internal lateral forces. Bridges like this would almost always remain standing, with the ground either side just crumbling away, especially as it can be seen from cab view videos there weren't even abutments.
I think the most telling photo however is this one (Source:
Network Rail):
View attachment 147767
Bridges don't bend like that, I very much struggle to see any way a landslide has put that much lateral force on the bridge. The bend also appears to be over the down lines, which would obviously be far more consistent with a bridge strike.