Fishguard Harbour, the nearest station to Dinas, is the end of the line. Your only options are to take the ferry to Ireland, at 2.30 am or 2.30 pm, or go south towards Carmarthen. As there are only seven trains a day, I can’t recommend it for a conventional train spotter. But the area is nevertheless full of reminders of what used to be or might have been.
- There are the remnants of lines at abandoned quarries, at Rosebush and Porthgain
- There’s still a line to the old Royal Navy Armaments depot at Trecwn where copper was used for the narrow gauge railway in order to avoid the danger of sparks
- There’s a line that was engineered and almost completed before being abandoned at the out break of the 1st World War. The bridges and embankments can still be seen
This bridge was built to carry an alternative line from Goodwick to Letterston that was never completed although a mile or so of embankment still remains to the west of it. The scheme was interrupted by the outbreak of WW1. © Copyright ceridwen and licensed for reuse under this Creative Commons Licence
- The route of the old North Pembrokeshire and Fishguard Railway dating from 1876 and finally closed in 1949 is still visible in places
The course of the old North Pembrokeshire and Fishguard Railway at Cil-moor. © Copyright Philip Halling and licensed for reuse under this Creative Commons Licence.
- There are abandoned halts (request stops) and stations on the Fishguard line.
So there is plenty of interest for railway enthusiasts in the area. You will even find that local farmers have put old freight wagons to good use as a feed-stores for the mountain sheep.
Old railway wagon on the mountain above Dinas
Tegfan, Dinas Cross 
Interested to hear about the virtually completed but then abandoned line.
Can I ask where this was and where the still visible bridges and tunnels are.
I have added a couple of pictures: bridges and embankments but no tunnels.
The planned 1912 route left the existing line just North of New Road off Wern Road, Goodwick. It then heads East of New Road past Dyffryn – the other side of the A487 to the existing railway. There is an underbridge near Ivy Bush Guest house and an overbridge near Mill Farm on the lane to Cwmbrandy common. Work didn’t start on the 2 tunnels, but between the existing Letterston Junction and Jordanston Halt there is a deep cutting which ends by the Jordanston – Scleddau road, clearly seen from the train. The 2 tunnels would have covered most of the route between Mill Farm and Jordanston – an expensive piece of line if it had been completed.
Llandarcy Oil refinery was planned for Scleddau Moor but the GWR wouldn’t give port access for oil tankers as they expected the Trans-Atlantic liners to return after World War 1 – they didn’t unfortunately. The liners were regular callers between 1909 and 1914 which was the driver for the new line.
Thanks – interesting! I wonder what Fishguard would be like now if it had become a regular stop for liners on the transatlantic route.