The Freightliner depot is easily visible from the bridge over the railway leading to the container port. Leave the main coast road (A33)at the A35 junction. Take the turning opposite the A35 signposted towards the port entrance (this is called First Avenue)but DO NOT CROSS THE BRIDGE BY CAR as there is no public access to the other side of the bridge (the bridge itself has safe public footpaths on both sides. Just before the bridge, turn right and park where you can (note this is a busy access to an industrial estate). Walk back onto the bridge where you will have good views of the depot, container yard and running lines. catering is provided by a small burger van just by the bridge or MacDonalds by the roundabout on the main A33.

With Southampton freightliner yards between these 2 stations which are a couple of miles west of Southampton and being on the main London to Weymouth line with the Salisbury line just a few hundred yards to the west this is a nice location. No facilities and only limited parking but then it is a quiet station where a variety of stock can be seen.
Just the other side of Redbridge station platforms a line is used as a head shunt to the container sidings.
With in a hour I saw a feightliner train being shunted, a Hanson stone train trundle through, Virgin Cross Country services and several passenger trains.