Testing and training of staff in the operation of new trains has started on the North Wales Main Line.
Three sets of cars, previously used on the East Coast main line, were due to be introduced on services between Holyhead and Cardiff during the December 2019 schedule change.
But delays in handing over the Mark 4 coaches from LNER, their former operator, to Transport for Wales (TfW) and the need to adapt them to work with Class 67 locomotives resulted in a delay.
In turn, this has led to overcrowding and cancellations on the network and the new trains may not be introduced until late spring.
The first drive of the new trains took place on Tuesday with the five-car train from Crewe to Holyhead. He then returned to Llandudno Junction and made the short trip to Llandudno before returning to Crewe.
The train made a similar journey on Wednesday and visited Manchester on Thursday.
The train, consisting of a first class car, two standard classes and a mixed standard / restaurant car, remains in basic-LNER livery with the TfW labels attached.
The Class 67 locomotive, originally built in the 1990s to carry mail trains, is leased from freight operator DB Schenker and has been repainted in TfW red and white.
The train operates in a push-pull mode with the locomotive pulling the train west and propelling the train towards Chester with the conductor operating the controls from a driving trailer.
Once in service, the trains are expected to make three trips per day between North Wales and Cardiff. A set will stay overnight at Holyhead.
Rail sources told North Wales Live that a set could also be used on a Holyhead and Llandudno service to Manchester as a replacement for the current train formed from old Mark 3 wagons.
The Mark 4 cars were part of TfW’s promise to passengers to introduce new trains to the network when the Wales & Borders franchise took over in October 2018.
In service on the East Coast Mainline with LNER, and previously with Virgin Trains East Coast, between London and Edinburgh, cars regularly reached speeds of 110 mph. But in service with TfW, they will be limited to a top speed of 90 mph on relatively short sections of track.
Three class 230 trains, formed from old London Underground wagons, have yet to make an appearance in North Wales. These are expected to operate on the Conwy Valley and Borderlands lines but have not yet been delivered to TfW.