In the past when I been working in Avonmouth near to the rail line it always struck me funny to see Virgin high speed trains and just about every one else using the line.
Quite a few times in the past they have used the line from Bristol to Avonmouth when they been doing line repairs to warrant diversions through Avonmouth then back towards the main line.
They spent millions of pounds on the spur in the pas as the rail line past Filton was sinking.The line is used mainly for container trains and cars in and out the docks,like wise with the Portishead line.
Pre-Beeching there was a reasonable suburban rail network around Bristol:
Temple-Meads/Portishead which is now freight-only as far as Royal Portbury Dock as you point out, which is still awaiting as a passenger route along its entire length. It would be a big tourist draw too with its route threading the Avon Gorge via a series of tunnels. Already the TM-Avonmouth route on the north bank of the Avon is regarded as a potential tourist attraction.
Filton/Avonmouth (which runs through the old Filton airfield site) the current freight-only line which it was hoped to restore to passenger services for the whole length but it now looks as though the passenger part will end at Henbury as a spur.
Severn Beach/Pilning Low Level/High Level that linked with the current Bristol/South Wales line and was a continuation of the current Temple Meads/Avonmouth/Severn Beach line.
Taking the last two with the current Temple Meads/Avonmouth via Clifton Down line, a series of loops around the north-west Bristol suburbs was the result. How valuable they would be these days as a sort of metro.
Temple Meads/Frome via Brislington and the North Somerset coalfields.
Temple Meads/Fishponds/Mangotsfield then via Bitton to Bath Green Park (the old Midland Railway line now a cycle path) or north to Yate and the Midlands. (Mangotsfield Station was the inpiration for the pre-war play 'The Ghost Train' (later filmed), written by Arnold Ridley better known as Private Godfrey in
Dad's Army and also a previous secretary of Bath Rugby Club
).
There were also lines from the Portishead branch at Ashton Gate to Canons Marsh (the area currently occupied by Millennium Square and Anchor Square on Harbourside) and via Wapping Wharf and Redcliffe tunnel to Temple Meads. Both were primarily goods lines but the Wapping Wharf line was occasionally used as a relief line on Sundays for some passenger trains going to the South-West if the main line via Bedminster was occupied for any reason, albeit I don't think such use occurred much after WW2. Part of the Wapping Wharf line from Princes Wharf near M Shed along the former dockside and then by the side of Cumberland Road to Ashton is still used regularly at weekends and public holidays by the standard gauge steam-hauled Bristol Harbour Railway and is extremely popular with tourists and other leisure users.
There were also stations that no longer exist on lines that are still open such as St Annes Park on the TM-Bath Spa line, and at Ashley Hill and Horfield on the line between TM and Filton, which as I mentioned earlier is being restored to four-track up the Filton bank.
With Bristol's horrendous traffic problems and poor public transport provision these lines and stations would be like gold dust if they were still operating.
