I went a couple of weeks ago and it was definitely operating from 13 30 onwards. I stayed overnight in Mallow - at the Hibernian Hotel in the main street, 15 minutes walk from the station - and caught the 09 26 train to Tralee on the Wednesday morning. After the famous double-reversal at Killarney, this is due to arrive in Tralee at 10 58 with a +2 connection into the 11 00 route 13 Expressway bus to Limerick. The train usually arrives 2-3 minutes early....and if you position yourself at the very front door of the train and go straight out of the side gate of the station and across the car park to the bus station, you should make the bus OK.
Alight from the bus in the main square in Listowel at about 11 30 and there are several nice cafes where you can have an early lunch, before the 15 minutes walk to the old station, beyond which you will find the Lartigue monorail museum and demonstration track in and outside of the former goods shed. The volunteers who run it are extremely welcoming and knowledgeable....but fairly elderly and perhaps not the most computer literate?
If you spend an hour and ten minutes there - including the short ride - you could walk back into town and catch the 15 00 bus (which was 22 minutes late due to traffic and roadworks) - from the same stop where you alighted - back into Tralee for the 17 05 train back to Mallow and Cork, with a connection at Mallow for Dublin. Alternatively, you could take a later bus from Listowel to Limerick and continue your rail journey from there.
I've tried to upload a couple of videos, but I'm afraid the files are too large. However it's very well worth making the journey to visit a lovely reconstruction of one of the world's most unusual and eccentric railways!