Partly depends on what sort of stuff you'd like. Wolverton offers 3 good spots:
- the station itself, which shows the Tilt off to it's full effect (it's a very sharp curve). The station is unbarriered as well, but parking can be awkward.
- the nature reserve just north of the station, where you can get some good shots looking up to the viaduct. Especially if you go a bit further away for the longer angle, you can see trains on the viaduct quite clearly from the bird hides
https://maps.app.goo.gl/mWSRwZ9Z7N6nS7F27. This is probably a 30-minute walk from the station at most.
- the 2nd bridge south of the station (H2 Millers Way) gives a good high angle over the lines, including the depot shunting sidings between the slow lines. If you're lucky/prepared you can see some very interesting things. IIRC The footway is wide on the north side of the bridge but effectively non-existent on the south side so you don't have the widest target. About 15 minutes walk from the station.
Wolverton Works is also worth a look from the Aldi Car Park, but not sure there's any good photo opportunities there. If you do stop at Wolverton I can recommend the Ole Tapas bar for lunch and Biergarten micro-pub in some of the old carriage works for refreshment, if they're open.