The Midland does seem to have had sidings down by the Floating Harbour, roughly where the GWR crosses it at the east end of Temple Meads.
These survived into the early 1960s. One of the key spotters' locations then was at the east end of the Up Main platform, which is almost out on a bridge over the river. Down below on the opposite side were various goods wagons, which a Class 03 shunter very occasionally worked in and out of, number too far away to read. It had apparently taken over a year or two before from old 0-4-0T 51218, long at Bristol and now preserved various tracks fanned out along the river, and across open streets, including right under the Temple Meads approach. The old Avonside loco works used to be here long before, who built various smaller tank engines, but they moved out to Fishponds, also on the Midland line, around WW1 time.
If spotting boredom set in a walk was in order right down to the end of the old Brunel station, wooden-boarded platforms, dim light, round the buffers at the end, and up the far platform, all was a near-ghostly fascination. Trains still used the eastern parts nearest the river, some Severn Beach trains, S&D trains to Bath Green Park with green Southern stock, and occasional Jubilee or Peak main line services to Birmingham. But the far end was never reached by these, and the offices there also seemed abandoned.
The "Floating Harbour" under that bridge was the old river, which had acquired various bankside industries and wharves over the centuries, and in about 1800 had been cut off by a river diversion which went under the other end of Temple Meads. Locks kept the old river, right through Bristol, at high tide for ships to access, but seagoing ships couldn't get above Bristol Bridge to these wharves.
