I'm surprised this tunnel hasn't had more reports on it over the years considering what's inside! It has an interesting history as well. It appears to go by a few names too, the most used being Hawthorns, although it's also referred to as Euroclydon and Puddlebrook Tunnel.
The History
One of many small branch lines in the Forest of Dean, the idea for the Mitcheldean & Forest of Dean Junction Railway was first mooted in 1871, with the intention being to link the small villages north of Cinderford with the GWR's Gloucester-Hereford Main Line via Ross-on-Wye.
In essence it was just an extension of their Whimsey Branch, and at only 3 1/4 miles long, a significant expense considering the requirement for two tunnels. Puddlebrook Tunnel was 638 yards in length following an S-shaped alignment, with the Drybrook Tunnel being to its south at a length of 97 yards.
Construction was beset with delays caused by contractual disputes, with work stalling by August 1878. The GWR had to intervene, investing a further £20,000 (£1.91m today) on top of its original investment to resolve the issues. By the summer of 1880, the line was pretty much complete, with transfer to the GWR taking place on the 6th August.
GWR took the decision not to open the line, with the reasoning behind this likely being due to the Severn & Wye Railway successfully opening their branch line through Lydbrook in 1874, which provided a through route from Cinderford to Ross-on-Wye, negating the need for the competing GWR line. The costs of modifications needed at their Mitcheldean Road station to accommodate the new branch may have also had an influence.
The southernmost mile was brought into use in 1885 to serve a goods station at Speedwell, with services extended as far as Drybrook Halt for a railmotor service in 1907, but this was short-lived, only operating until 1930.
The track to the North was lifted in 1917, although it was relaid as far as Drybrook Quarry in 1928. Puddlebrook Tunnel was converted into a munitions store for the Admiralty at the onset of WW2, and the line was relaid up to the tunnel to serve this.
It was used to store Depth Charges, Mines and Torpedoes from the nearby Royal Ordnance Factories at Glascoed and Swynnerton. The narrow gauge railway that remains in situ on the east side of the tunnel today was installed to facilitate this, along with steel framework for weapon storage. Lighting was also installed throughout. The site was protected by steel fencing and a guard hut at either end of the tunnel.
The site received regular workings of 7-8 wagons full of munitions, which was processed in a large transfer shed just outside the southern portal. They were then moved into the tunnel by one of two pony locomotives serving the stores.
The branch line was closed for good in February 1953, with the track being lifted in 1957. It would appear the Admiralty abandoned the majority of their railway equipment within the tunnel, with it being discovered by the Royal Forest of Dean Caving Club in 2012.
A heritage group was formed following this discovery, and they have established the Lea Bailey Railway to the north of the tunnel, near the site of the old Lea Bailey Gold and Iron Mine. I'm not sure whether they utilised track from the tunnel, or sourced it from elsewhere, as some is definitely missing given how abruptly it stops.
The Explore
Took a wonder up the nearby footpath first to make sure the portal wasn't totally bricked up like a lot in the Forest of Dean are. Seeing that it wasn't, I found my way into the cutting, walking through the wide open very rusty gate that I'm assuming was part of the WW2 security fencing from the state of it.
Found some old, rusting machinery including what I'm assuming is one of the two Admiralty pony locos in a sorry state outside the south portal. Couldn't see any signs of the transfer shed, but the decaying machinery was likely from it.
Hunslet Locomotive -
Bit of gauge goodness -
Understandably of a Flameproof design -
Oil Filter is in surprisingly good condition -
No idea what this contraption was used to be -
The South Portal -
The North Portal -
Wandered down into the portal, and my heart started to sink seeing the doors hiding within, but luckily for me they were open!
Spotted what I'm assuming is an old insulator that's in good condition just outside -
Turned on the brand new Olight and was very pleased to see all the abandoned wagons and trackwork running down the tunnel. Used to seeing mud and the odd calcite deposit, so made for a decent change.
Found the other pony loco in much better nick under a cover... There's a lot of water ingress above it, but the cover it's under is doing its job relatively well, as it looks almost pristine compared to the rusting hulk outside. Didn't attempt to remove the cover as I was solo, too much of a faff with how wet it was.
Curious how there's pretty much no mileage on that odometer -
The trackbed is a tad muddy underfoot, had to walk on the tracks in the spots that weren't concrete lined. The tunnel is described as being very dry, but there was a lot of water ingress in quite a few places. Made for a few nice calcite formations though.
Just beyond the end of the tracks, the tunnel lining looks to be failing. Was hard to get a shot where you can see it clearly, but there was a slight bulge in the roof, and it has started to crack along the edge of the bulge.
Was appreciative of the changes between lined and unlined towards the northern end, made for some good shots whilst experimenting with the new torch.
There's what appears to be some old radiators, and a small little crane at the northern end, with the doors this end also being unlocked.
Trackbed beyond appeared very boggy, but clear, so you could walk it if you so wished. I don't think the nearby Lea Bailey Heritage Railway extends beyond Hawthorns Road, but there's definitely scope for them to expand, potentially why the trackbed was so clear.
The way out, with another surviving insulator -
Thanks for looking!