Of the 10 Great Little Trains of Wales’ most celebrated narrow-gauge railways — here are highlights of the top four:

Talyllyn Railway

The train embarks from the hamlet of Tywyn on the Cardigan Bay coast and runs just over seven miles through the Fathew Valley to Nant Gwernol, a station with no road access but plenty of forest trails worth exploring. Driver Chris Parrott, whom Americans would call the engineer, says that Talyllyn is the first preserved railway in the world. The typical round-trip takes two and a half hours — an hour each way and a half hour at the end of the line for a walk or tea.

Travelers should allow time to visit the Narrow Gauge Railway Museum at Tywyn Wharf. The collection spans two centuries of railway history, from locomotives to signs, tickets and signaling equipment. It’s also where I learn that Thomas the Tank Engine’s creator, the Rev. W.V. Awdry, was an early volunteer at Talyllyn, and his Skarloey Railway engines are modeled on Talyllyn’s locomotives. 

Ffestiniog Railway

Located in the handsome port town of Porthmadog, this line was established in 1832 and runs 13.5 miles through Snowdonia National Park to the slate mines at Blaenau Ffestiniog. It’s a 700-foot climb to the mines from sea level, and when the railway first opened, horses lugged wagons uphill, then gravity pulled the slate-filled trains down to Porthmadog. Today, there are several tight turns, including a complete spiral, which is only possible because the railway is so narrow (23.5 inches).

The train huffs through residential neighborhoods at a top speed of 20 mph and comes so close to the windows of compact homes that passengers actually can see family photos atop dressers. The singsong sounds of bleeting sheep bounce around the hills, while sapphire lakes shine through the afternoon drizzle.

Most of the railway is single track, but at four places, including at Tan y Bwlch (the ‘w’ in Welsh can be a vowel and sounds like our “oo”), the track splits into two are two tracks. At these stops, the train driver must disembark and go into the trackside station house to remove a foot-long, notched “token” to continue on. Each of these token machines are linked by telegraph to the next station. Explains Andrew Thomas, a spokesman for the Ffestiniog railway, “The machines are interlocked, allowing only one token for the section to be removed at a time.”

For a final safety check, the driver then must show the train’s guard and fireman the token, and they read aloud the station names stamped on it to ensure it’s the correct token for the section about to be entered. The ingenious system, devised about 150 years ago, prevents head-on collisions by ensuring that trains pass one another on separate tracks before continuing along the single track that makes up most of the line.

Once reaching Blaenau  Ffestiniog, riders can hike over to the slate mines or watch as the engine is detached and pulled around to the other side of the train for the return journey.