From next April the public will be able to travel by steam for almost 40 miles through the Snowdonia countryside
The final step in the creation of Britain's longest narrow gauge railway will be taken this weekend.
For the first time, the Welsh Highland Railway will carry passengers along the whole length of the newly-laid line between Caernarfon and Porthmadog.
When linked up with the Ffestiniog Railway at Porthmadog's Harbour Station, it will be possible to travel by steam for almost 40 miles through the Snowdonia countryside.
The new line will open to passengers in April 2011, but this weekend's trips have been laid on especially for those who've helped contribute more than £2m towards the restoration work and the volunteers who gave up their time to lay the track.
Saturday, 30 October, 9am, first train leaves Caernarfon, crossing Britannia Bridge, Porthmadog, 11.25am.
Second train departs 11am, arriving at Porthmadog 1.40pm.
Trains return to Caernarfon at 12.50pm and 2.55pm.
Sunday, 31 October, 1.15pm, train departs Porthmadog hauled by Lyd, the world's newest steam locomotive, built at the railway's own workshops.
Other enthusiasts can watch the trains running down the tramway section on Porthmadog's High Street for the first time since the original railway closed 79 years ago.
The trains will also cross over the Network Rail line at Britain's only standard gauge/narrow gauge level crossing.
"It will have the first train running the length of the line with genuine passengers," said Andrew Thomas, spokesman for the Ffestiniog and Welsh Highland Railway (FWHR) who are responsible for all the track between Caernarfon and Blaenau Ffestiniog.
"The journey will currently take around two hours, because it takes a few years for the new track to bed in. Eventually, we will be able to run at the maximum of 25mph, and the journey will take one and a half hours."
The work on this line began in the early 1990s and has cost £28 million in total. Partly funded by grants, the rest of the money was raised by donations from sponsors and the public.
Over 1,000 volunteers have helped lay the track, and Andrew is delighted they and their families will be the first to enjoy the trip.
"Everyone always says the best part of the line is through the Aberglaslyn Pass, because it's much better than driving it in a car," said Andrew.
"But my favourite part is the flat section down towards Porthmadog, mainly because you're surrounded on three sides by mountains. You have a majestic, panoramic view of Cnicht and Snowdon; it's really impressive."
The FWHR say the steam railway generates up to £15m a year for the Gwynedd economy and creates an estimated 350 jobs in the area.
Special sherry and mince pie trips from Porthmadog to the Glaslyn Valley will be held from early January when the Ffestiniog line will be closed for maintenance work for six weeks.
There will also be trips from Porthmadog to Caernarfon during February half term.