Our local operator, First Great Western, is one of Britain's best in provision for cyclists. You can read a guide to travelling with bikes on their website.
For a really trouble-free ride, hire a bike along the route. But if you want to take your own bike, here are some extra tips so your journey goes smoothly.
Trains on the Cotswold Line are either seven/eight-carriage High Speed Trains ('HSTs') or two/three-carriage Turbos. HSTs are marked with an H in the timetable.

HSTs have space for up to six bikes, in a special compartment at the end of Carriage A. This almost always stops at the country (western) end of the platform. Please arrive in plenty of time and stand at the right end of the platform. If you're bringing your bags into the carriage, rather than leaving them on the bike, detach them in advance so that the train doesn't have to wait for you to do so.
When the train arrives, use the special door at the end of Carriage A, marked with a bike symbol. Don't lock your bike anywhere to the fittings. Leave the compartment by the same door and quickly enter the train by a normal door (note that the rest of Carriage A is a quiet, mobile-free carriage). Be ready to leave the train immediately at your destination station.
At Evesham and Worcester Foregate Street stations, different stowage arrangements may apply, because of where the train stops. The conductor can advise you if this is the case.
Cycle reservations are not generally required on the Cotswold Line, though they may be advisable if you want to guarantee passage. We have never been turned away from a Cotswold Line train due to lack of space, but just in case, bring a lock in case you have to leave your bike at a station.

Some three-carriage Turbo trains have a small dedicated bike area in the central carriage. This is marked on the outside of the train.
Otherwise, you can carefully stow your bike in the vestibule (door area) of the train. Please sit nearby so that you can move it when required.
To help you not to block the doors, note that at Worcester (both stations), Evesham, Moreton-in-Marsh, Kingham, and Shipton, there are two platforms, so the door will open on the 'outside' of the track. At Pershore, Honeybourne, and Ascott, there is one platform only, on the south side. At Charlbury and Hanborough, there is one platform, on the north side.
There is a train every hour or two throughout the day. Note that the line is being upgraded to restore double tracks on some sections, so there may be engineering works at weekend. Replacement buses don't carry bikes.
Please try and avoid weekday peak trains. These are busy with commuters and have very tight timings. You are unlikely to find space for your bike on peak trains. In particular, the 'Oxfordshire Halts' train on weekdays (calling at Combe, Finstock, Ascott and Shipton) has only two carriages, can be exceptionally busy, and does not have space for bikes.
