* Black Five No.45337 departing Llangollen station.
The Ivatt Class 2 mixed traffic engine, No.46521, was once allocated to Machynlleth shed and was hauling trains on the Cambrian Coast line and round to Dolgellau in the 1960s.
During that period it also pulled the Royal Train on a visit to the Cambrian Coast.
At the gala event, on Friday and Saturday, it will be joined by three members of the Llangollen home-based fleet, with the British Rail Standard Tank engine No.80072 and the Black Five No.45337 making a welcome return to service and the Great Western Heavy Freight engine No.3802.
They will be joined by one of the British Rail Class 26 heritage diesel locomotives No.D5310 as the railway sets out to imitate railway operations down the line to Barmouth on the Western Region before Dr Beeching took his axe to the network in 1964.
The special timetable, entitled "Along Western Lines" for the gala, will see trains departing Llangollen at frequent intervals throughout each day, from 0900 onwards, for the run along the Dee Valley to Carrog and through to Plas Bonwm on the extension of the line.
A demonstration freight train is included in the sequence of departures and on Saturday an evening service will operate.
During the gala there will be a photographic and railwayana display in the tearoom at Berwyn station covering the course of the railway between Ruabon and Barmouth.
This will include maps, original engineering drawings and historical paperwork, as well as a photographic record of the stations along the line.
For thirsty rail fans there will be a real ale bar in the Henry Robertson suite at Llangollen station, as well as real ale served on trains.
George Jones for Llangollen Railway said: "We have another spectacular occasion when visitors will see how the railway might have operated at full capacity in the years prior to the infamous Dr Beeching's Report 'The Reshaping of British Railways.”
On an historic note, he added: "This year is when we mark the 50th anniversary, in December, of the last through train running between Ruabon and Barmouth due to flooding which washed away the track near Llandderfel.
“Only the sections between Ruabon and Llangollen and Barmouth and Bala retained shuttle train services prior to formal closure of the line in January 1965.
"No one thought then that the railway at Llangollen would make a comeback, but it has, and it will shortly achieve its aim of reconnecting to Corwen once the extension work is completed and the line has passed its official inspection."
Details of the timetable and fares are to be found on the Railway's website at: