No trains between Leagrave & St Albans.
So l think it is the other stations that are getting worked, which means no trains to Parkway.
It is Luton platforms work driving the work schedule. Overhead wires need to be off. Having planned for that, other works take places at other stations, including Harpenden as I understand it, the combined effects of the whole lot preventing EMT as well as FCC trains.
Not good for LTN but I you have to break eggs to make an omelette.