Engines from our Collection

Compiled by Gareth Jones

The PL Class locos were built by Kerr Stuart as a batch of three locos to the gauge of 2ft 6. They were 20 ton 0-6-4T locomotives with small (27 inch diameter) coupled wheels and an axle load of only 4.75 tons.

The railway they were built to run on opened in 1900 as the Parlakimedi Light Railway, however the PLR was taken over by the Bengal-Nagpur Railway (BNR) in 1902. In1928 a batch of these engines was ordered and they were to become the standard class for the line with a total of 8 engines of the type working on the line up to dieselisation in April 1992.

Amzingly for such a small loco class six of the locomotives from this railway have been preserved; PL 691 has been plinthed outside Southern railway headquarters, Chennai, PL 692 has been plinthed outside BNR hotel, Puri, PL 693 has been plinthed on the Ramakrishna beach, Vishakhapatnam, PL 694 has been plinthed outside the Vishakhapatnam station, PL 697 has been plinthed outside DRM office,Vishakhapatnam, and finally our engine No.695 is stored as part of our collection until the day it goes on public display in our new museum.

Whilst a number of photos exist of these engines, during the research for this article I could not find a single image of our engine No.695, most photos feature No.696 as the one above.

180-year-old underground waterwheels discovered in mid-Wales

by Ioan Lord

In March 2023, the remarkable and unique discovery of two, large and intact underground waterwheels was made at an old lead mine near Aberystwyth, mid-Wales. The waterwheels, which measure 16 feet in diameter, were found to be constructed almost entirely of wood and are at least 178 years old.

Not only are these the second and third underground waterwheels known to have ever been found completely intact in a Welsh metal mine, but they are the only complete wooden ones yet found in Britain and are believed to be the oldest. Both are survivors from the mid-nineteenth century technological revolution in British metal mining. The mine’s identity is being kept anonymous due to landownership sensitivity and the safety of the superb relics that have been found.

Four adit levels were driven east along the mineral lode during the second half of the eighteenth century. The richness of the orebody resulted in vast stopes soon connecting all four levels underground. In 1840, for the first time, the workings were sunk below the lowest (No. 1) adit. This meant that the water would have to be pumped up to that level in order to drain out to surface, and that the ore would also have to be hauled up to be carried out. Two winzes were sunk below No. 1 Adit, 120 feet apart and nearly a quarter of a mile inbye. The western winze was called the Cornish Sink, and the eastern was called the Welsh Sink, probably referring to the nationality of the miners who were employed in sinking them. Both were sunk to depths of 10 fathoms, where a 10 Fathom Level was driven to connect them. The mine’s investors made provision for a rare technological installation for the time: a pair of underground wooden waterwheels which were erected at the head of each winze. The one at Cornish Sink was installed in No. 1 Adit to draw (wind) the kibbles of ore from the deeper levels. The one at Welsh Sink was erected in a stope above No. 2 Adit to operate a pumping system. The reason for the wheels being in different adits was so that the water from the highest (pumping wheel) could be reused and fed down the stopes to drive the lowest (drawing wheel). These waterwheels as well as their associated machinery were carried in by hand piece by piece, over 800 feet into the mountain through low and narrow passages, and installed 350 feet below surface by dim candlelight.

A long project to find and record the underground workings at this mine was undertaken by Ioan Lord and Tomasz Zalewski between February and March 2023. This involved accessing areas where nobody had ventured since the departure of the last miners well over a century ago. No. 1 Adit had been accessed as far as Cornish Sink by the North Cardiganshire Mining Club in 1978, but the exploration was aborted short of the waterwheels. The 2023 Lord-Zalewski exploration first examined No. 1 Adit and found it in relatively good condition with a 1’6” gauge tramway still intact on the floor. Cornish Sink, the drawing winze sunk below No. 1 Adit, was reached on 24 February and the first waterwheel was discovered shortly thereafter. The second waterwheel, situated 80 feet higher above No. 2 Adit, took several days of bolting and rigging to reach and is situated in a much more precarious and dangerous area amongst collapsing stulls and platforms. It was finally reached on the night of 17 March, and light was shone upon the remarkably intact construction for the first time in over 120 years.

The first wheel – Drawing Waterwheel

The drawing waterwheel was the first to be discovered, and was totally buried in collapsed debris when first reached. The site of the wheel was said to have been found during the 1978 North Cardiganshire Mining Club exploration, but since extensive rigging would be required to physically reach the wheelpit (which stands 20 feet above the No. 1 Adit floor) it was not examined and the club claimed that the wheel was merely a collapsed ‘pile of broken wood’. It also claimed that the wheel would have been a special type known as a kerrhad: a reversible waterwheel with buckets facing both directions so that kibbles could be raised and lowered without having to disengage the winding drum. The 2023 Lord-Zalewski exploration has disproved both claims. The masonry wheelpit was climbed using SRT rigging, and the large debris pile on top was closely examined. Some debris was removed, which revealed that the waterwheel remained intact underneath. Traces of orange paint even survived on the wooden felloes. A portion of the structure was exposed in order to conduct a partial survey. It is a conventional type with buckets facing one way only (therefore not a kerrhad), measuring 3 feet breast and c.16 feet diameter. It is placed in a masonry wheelpit built on the bedrock floor of a stope 20 feet above No. 1 Adit. The buckets, felloes and arms are made entirely of wood, but each arm is connected to the felloes by an iron T-shaped shoe. The wooden sole plates on the exposed section have partially fallen away due to the debris which collapsed on top of it. The hub and axle have not been examined owing to the debris which still buries the bulk of the construction.

Two partially-overlapping 3-footdiameter iron sheave wheels are mounted in the stope 30 feet west of the waterwheel, which formerly guided drawing/ winding chains powered by a drum fixed to the wheel axle. This drum was known as a drawing machine. There was formerly a pair of smaller sheave wheels, measuring 9 inches in diameter, which the chains passed under immediately west of the end of the wheelpit, but since the 1978 exploration these have collapsed. The two drawing chains were coiled in opposite directions around the drawing machine, so as the waterwheel revolved, one chain would raise and the other would lower. The chains (of which one survives) passed over the 3-foot sheaves and descended Cornish Sink (the drawing winze) to raise and lower kibbles (iron buckets) of rock. Cornish Sink is sunk on the steep underlie of the lode, and contains a wooden kibbleway along which the kibbles were designed to slide. This consists of 6-inch-diameter skinned larch pole runners for guiding the kibbles, with boards laid in between them. Immediately below the sheaves is a landing plat, reached by still-intact wooden ladders, where miners received the full kibbles and tipped their contents into a wooden hopper. A brake shoe mounted on the drawing machine would have allowed the operator to stop the kibble level with the landing plat, so that the lander could lock the chain using an unusual pair of blacksmith-made tongs which was chained to a nearby stemple. The tongs would stop the chain holding the kibble from moving whilst the lander tipped its load into the adjacent hopper. The contents of the hopper was then emptied into 1’6” gauge tram wagons in No. 1 Adit below, which were then trammed to surface.

No remains survive of the feeder launder which supplied the Drawing Waterwheel, but it is certain that the

1. Drawing Waterwheel

2. Sheave wheels

3. Locking tongs

4. Tail race launders from wheelpit

5. Kibbleway

6. Ladders and platforms for accessing Landing Plat

7. Tail race launders discharge water onto No. 1 Adit floor

8. Cornish Sink (sunk below No. 1 Adit)

9. Landing Plat (for unloading kibbles)

10. Ore hopper with protective planks covering launders water was directed from the tailrace of the Pumping Waterwheel in the level above. Parts of the launder system remained in 1978, and were said to consist of square, 6” internal diameter box-launders coming down the side of the stope, each section connected to the next by conical male-female tapers. However, the launders which carried the tailrace away from the Drawing Waterwheel still survive largely intact. They take the form of large, square box-launders 1 foot in diameter, exiting the base of the wheelpit and running along the wall of the stope through Cornish Sink and the ore hopper. They are fixed to the wall of the stope by iron brackets. 20 feet west of the ore hopper, the launders change from running nearly horizontal to almost vertical. This would have discharged the water from the waterwheel onto the floor of No. 1 Adit, where it naturally drained to the surface. Heavy planks have been laid to protect the box-launders where they pass through the ore hopper, to avoid damage caused by falling rocks.

The second wheel – Pumping Waterwheel

After the discovery of the Drawing Waterwheel under the debris on 10 March 2023, it was decided to push even deeper into the old mine workings and attempt to find the Pumping Waterwheel. Nobody had ventured further than the Drawing Waterwheel since the closure of the mine over a century ago, and thus the condition or even the existence of the Pumping Waterwheel was totally unknown. It was reportedly situated 80 feet higher than the Drawing wheel, in a stope above No. 2 Adit. The next stage of the 2023 exploration required extensive SRT rigging to climb up through several stopes in between the two adits. The stopes were in poor condition and most of the false timber floors were nearing the end of their lives, but after bolting and rigging three more rope pitches, No. 2 Adit was attained. There are many collapses which now prevent direct access to this point from the original adit portal, which was situated 600 feet to the west. The Pumping Waterwheel was found at 11:30pm on the night of 17 March. It is situated in a stope directly above the roof of No. 2 Adit, and survives completely intact and entirely visible. Light shone upon it for the first time in a hundred years revealed its remarkable state of preservation. It measures 16 feet diameter and 3 feet breast, and has been constructed almost entirely of wood. The axle is a single, square-cut timber 1’6” thick, and on each end a circular iron casting is fixed to iron stubs which sit in two axleboxes. The iron axleboxes are of conventional design and are fixed to heavy timber baulks which form the wheel-frame. On the east end, the frame is supported by timbers built into the walls of the stope, but on the west end the frame rests on a drystone wall. The northern side of the frame has collapsed, leaving the northern axlebox hanging in mid-air.

Unlike any of the other known underground waterwheels which survive in Britain, the waterwheel’s design does not consist of cartwheel-like arms fanning out from the axle. Instead, there are two sets of parallel arms which span the diameter of the wheel at every quarter turn. They are not bolted or fixed to the axle, but merely held to it by simple wooden chocks which have been hammered in on each face (see diagram). Flat iron plates have been bolted across each spot where the arms cross, near the centre of the wheel, for strength. The felloes forming the circumference of the waterwheel consist of an inner and an outer ‘layer’, which is clearly visible in the photographs. Iron cross-ties run between the inner felloes at semi-regular intervals to support the structure.

All that remains of the feeder launder for the pumping waterwheel is a c.1foot-diameter box launder which drops vertically through the roof of the stope 16 feet above the wheel-frame. The next level above the waterwheel is No. 3 Adit, whose portal is situated near a brook. It is very likely that the stream, augmented by a leat which passes by its headwaters, was directed into the adit in wooden launders before passing down through the stopes to the Pumping Waterwheel. No remains survive of the tailrace launder which carried the water on down to the Drawing Waterwheel.

Connected to the iron stub at the south end of the Pumping wheel axle is a large iron crank, to the end of which is connected two, 1”-diameter iron rods. The rod leading to the west connects to a large, completely intact balance-bob set in a rock alcove. The bob consists of a 5-foot-tall vertical kingpost, connected to the end of a 5-foot-long horizontal rocker arm. The ends of each post are connected by diagonal iron stays and a support beam. A partially-collapsed wooden box is fixed to the west end of the rocker beam, which, filled with rock, counterbalanced the weight of the associated pumping machinery. The rod connecting the bob to the waterwheel passes through a slot near the top of the kingpost and is joined to the stays. The bob is pivoted at the base of the kingpost, with a small iron axle passing through two axleboxes fixed to timber baulks on the floor of the alcove.

The rod leading east from the waterwheel crank is the sweep rod, and connects to a small, well-preserved angle-bob. The angle-bob is like a double-ended version of the balancebob, but exists solely to transfer the motion of the sweep rod from horizontal to vertical. The vertical pump rods which are connected to the end of the angle-bob only measure an inch in diameter, and descend clumsily through the partially collapsed stopes for 100 feet vertically to reach Welsh Sink (the pumping winze below No. 1 Adit). Being situated above No. 2 Adit, the waterwheel had only to pump the water as far as No. 1 where it could naturally drain to the surface. The pump rods running down through the stopes are guided by thick iron rollers mounted on timbers. Their condition at No. 1 Adit, at the head of the pump itself, is not known due to a collapse preventing access. It is probable that the rods entered the rising main here, where they powered a plunger pump within the pipe. A wooden cistern at the head of the rising main would have directed the water into No. 1 Adit to drain out to surface.

The design of the remarkably-preserved Pumping Waterwheel is unique amongst the three now known to survive

1. Balance-bob

2. Section of waterwheel with felloe removed to show buckets and sole-plates

3. Section of waterwheel showing detail of side, including inner and outer felloes, iron braces and sole-plates

4. Projection of feeder launder (no longer intact)

5. Feeder launder (still intact)

6. Pumping Waterwheel. Axle is connected to a crank which powers the pumping rods

7. Angle-bob

8. Pumping rods descending Welsh Sink underground in Wales. Its largely wooden construction, and particularly its two sets of parallel arms, bear striking similarity with the Medieval, German waterwheels depicted in Georgius Agricola’s De Re Metallica of 1556. No other nineteenthcentury mine waterwheels in mid-Wales are depicted with this arm design.

Significance of the discovery

In conclusion, the discovery of these two, 180-year-old waterwheels in March 2023 has more than doubled the number of underground waterwheels known to survive totally intact in Wales. They are also the only wooden underground waterwheels from their time that are known to still exist in Britain. It has enhanced our knowledge of early- to mid-nineteenth-century waterwheel design and installation, serving as the oldest complete underground shaftpumping and drawing arrangement still visible in the country. These two wheels, along with their machinery, had stood in total darkness for over a century until light was first shone upon them one cold, dark night in March after many days of underground exploration.