Yes there is a roadmap : https://forums.dovetailgames.com/threads/roadmap-update-6th-april-2021.38364/ The streaming schedule has not been officially released yet.
There is the roadmap stream tonight and probably have Wednesday being the usual workshop stuff and Thursday being a stream on clinchfield
https://forums.dovetailgames.com/threads/railfan-tv-schedule-6th-april-–-8th-april.38378/ According to this it says all streams start at 19:00
19:00 UTC is 20:00 BST (British Summer Time) the clocks changed in the UK on the 28th March. BST changes, but UTC remains constant, hence the change to 19:00 UTC which is then still 20:00 UK time.
BST doesn't change, what really happens is we just switch time zones from GMT (which is the same as UTC) to BST. They've said that for the avoidance of doubt, stream times will always be in UTC.