The 1000-1890 series 4-car sets were introduced into service from 6 May 2021 as part of Batch 20.
These are the first trains in the fleet to feature rotating banks of
seats; they can be arranged in a longitudinal or transverse seating
configuration when required. The seats are similar to those used on the
2100 series but are 10 mm (0.39 in) wider.
Power sockets are also provided. They are also the first trainsets in
the fleet to feature toilets; car 2 features a universal-access Western
toilet, and car 3 features a men's toilet. The trains are intended for use on reserved seat "Wing" services as well as chartered event services.