Machynlleth<>Tywyn trains are in the public timetable from now until the line goes back to normal.
My guess is that it is related to the roadworks in Barmouth which started today. The coaches which were used for the semi-fast do not fit under the bridge that is now the route avoiding the roadworks. Instead single decker buses are in use Machynlleth-Barmouth with the coaches still running Barmouth-Pwllheli.
So I guess Tywyn trains have been added to reduce load on the bus+minibus replacements. Both still seem to go via Tywyn though.
[Correction]
The timetable has no northbound service, apart from the first, between Machynlleth and Barmouth stopping anywhere other than Tywyn. The journey planner therefore gives ridiculous times involving doubling back via Barmouth or Harlech, e.g. Machynlleth to Morfa Mawddach takes 3h40 all day long.
It looks as if the minibus service was deleted rather than the through coach when this week's changes were made.
This must be an error. Anyone have rapid influence with TfW to get it sorted out?