‘Ralph’ (91.016) is a South African Railways 91.000 class narrow-gauge Diesel electric locomotive.
91 class introduction
Between September and December 1973, South African Railways (SAR) placed twenty 91.000 class General Electric (GE) ‘Universal’ series type UM6B diesel electric locomotives in service on its narrow gauge Avontuur Railway between Port Elizabeth in the Eastern Cape and Avontuur in the Western Cape. Some of them later also worked on the Alfred County Railway in KwaZulu Natal.
The 91.000 class GE UM6B diesel electric locomotive was designed and built for the South African Railways by General Electric in Erie, Pennsylvania. They were delivered in mid 1973 and numbered 91.001 to 91.020. The class was designed for two foot (610 mm) narrow gauge and is the largest two foot gauge diesel electric locomotive in the world at a maximum weight of 48 tonnes.
As a result of the severe clearance problems presented by the narrow gauge, it was not possible to follow the usual practice of axle-hung traction motors. Special bogies had to be designed with both traction motors mounted between the axles and with one traction motor on each side of each bogie.
91 class locos have air, vacuum and dynamic brakes. A lag control was incorporated into the train’s brake pipes to prevent bunching of the wagons upon braking and snatching upon restarting. This, combined with the cabling required for multi-unit control, resulted in seven connections between consisted units.
The class was very successful in operation, quickly displacing steam locomotives from the heavy limestone trains they were mainly purchased for. They were used in consists of up to three locomotives to haul the heaviest trains. As track upgrades progressed (to handle their 12 tonne axle load) their sphere of operation widened until even the modern and popular NG15s were mostly replaced. Eventually by the early 2000s, and after the deregulation of South African road transport, work began to dry up for them. Several were scrapped but some survived to be regauged and sold on to other operators. There are now class members in Argentina, South Africa, Madagascar and the UK. For a time the Apple Express used one and two others were sent to work on the Paton’s country railway in KwaZulu Natal, although that line has since closed.
91.016 history
Ralph was sold out of service by Transnet (South African Railways) to Pretoria based RRL Grindrod Locomotives Pty Ltd in the 2000s, who regauged it to 3’6″ by cutting the trucks into three pieces across the bolster and renumbered it to 91-04. They also changed the drawgear to accept a higher mounted, standard gauge sized AAR ‘Janey’ coupler.
Grindrod used it on contracts hauling ore until it either failed or they went out of business. It is not actually clear which one happened first but some minor parts had been removed before arrival at Sandstone.
It was then sold to Sandstone Estates as a source of spare parts for their other 91s, 91.010 and 91.019. DLRHT was actively looking for a 91 class locomotive as they are such an iconic part of 2 foot gauge locomotive development, and it rapidly became clear that opportunities to preserve one were quickly running out. Because 91.016 was at risk of scrapping the trust moved to acquire it and reached an agreement with Sandstone to do so in 2023.
Exciting progress ; I travelled behind one of Ralph’s siblings at Sandstone a few years ago so I am pleased to learn so much here about these impressive locomotives.
Restoration
8th June 2026
The new coolant gallery cover has arrived from CAT. It’s the first time we’ve ordered parts for Ralph’s engine and it was a positive experience.
3rd June 2026
Cutting the front pilot off Ralph is now about half done. Controlling heat build up in the front of the locomotive to limit any chance of warping is time consuming, but progress is being made. The handbrake brackets are on the inside of the pilot, and have been cut out ready for tidying and welding to the new pilot.
Two pallets of roof and engine parts have returned from blasting and painting and have gone into storage. One of the coolant gallery covers is too corroded to be reused but there is fortunately one still available from CAT Grimbergen which has been ordered.
13th May 2026
The process of removing the corroded and collision damaged front pilot from Ralph using a plasma cutter. The metal is very thick so it is quite a time consuming process, and to safely handle the parts when they are removed they have to be small enough to be easily pushed on to the forklift.
7th April 2026
Ralph’s new pilots have arrived. The photo below is an interesting comparison between the adapted pilots on the loco and the original style replacements.
19th March 2026
Ralph’s new pilot and coupler assemblies are now complete and ready to come to Sheffield for fitting. They should arrive at the start of April.
- Photos courtesy of the Ffestiniog Railway.
13th March 2026
The driver’s window is now mounted, drilled and countersunk for its new screws. The fireman’s side is mounted and partially drilled.
11th March 2026
The fireman’s side of the cab is now ground smooth. The new driver’s side window assembly has been test fitted and looks wonderful. The first batch of sand blasted doors, etc. has been delivered back and put into clean storage.
17th February 2026
More panel removal has taken place, with the last of the grills and doors sent away for sandblasting. Large amounts of cleaning to the engine bay and foot plates continues, with 1-2cm of ore dust, oil and grime being laboriously scraped off with a combination of heat, hand scrapers and angle grinder tools.
The Caterpillar special tool set for turning the engine over with a normal wrench has arrived from the USA, and will be of great help during the overhaul work.
12th February 2026
There has been a large amount of progress on Ralph over the last month. Work has concentrated on removing grills, panels, doors, hand rails and engine parts.
The engine is currently seized and wouldn’t turn with a bar. Two stuck valves have been found – one unseized with some gentle persuasion but one is stubbonly stuck. It is very probable that all the heads will go away soon for rebuilding and new valve guides though.
Even with the rockers off the engine still will not turn, so further bottom end investigation is necessary. The Caterpillar special tools needed to turn the engine slowly in both directions have been ordered from the USA. Further stripping will take place and an attempt made to turn the crankshaft every time a stuck part is removed.
Huge amounts of time are being spent removing ore particles, grease, oil and dirt from the locomotive. It’s not very visually rewarding in the short term but it is very necessary. The next steps are further removal of any removable panels ready for blasting. The cooler assembly above the brake cabinet is the next to be lifted off when it is unbolted.
27th January 2026
The fireman’s side cab recess is now fully welded in. Work is concentrating on removing the access doors and roof panels from the long hood in preparation for work to ascertain the condition of the diesel engine. It is said that it has a tight spot when rotated so that’s the first thing that will be looked at. The removed parts will eventually go for sand blasting and priming then be stored. Large amounts of built up ore, oil and general dirt are being cleaned out of the engine area as well, along with many disgarded fasteners and small parts that have been dropped over the years. These are being soaked in de-greaser incase they are needed.
15th January 2026
The fireman’s side cab recess is now tacked in place. There are some small repairs to do to the front of the cab. The next task after that is fettling of the sliding window apertures and drilling holes for the new screws (which have been ordered). The new windows were made in the UK and differ very slightly in profile to the South African made ones that were previously installed. After that the cab will be prepped for paint.
14th January 2026
Jon Whalley at the Ffestiniog Railway has sent these photos of Ralph’s new pilots after their return from the shot blasters. These are now almost ready for shipping to the Trust’s workshops for fitting.
Photo credits: Jon Whalley/Ffestiniog Railway
6th January 2026
Further paint finish testing is ongoing on Ralph’s noise. Experience is needed on the techniques required to give a good finish on the large expanses of flat panels that Ralph has.
29th December 2025
In preperation for the fitting of Ralph’s new pilots and couplers some of the new brake parts have arrived. These will allow the fitting of UK narrow gauge style air pipes to supplement the larger AAR ones fitted from new. These will be mounted on each side of the pilots in a similar way to multiple unit pipes on full size US locomotives. Knorr Bremse AAR spec MU fittings and Wabtec flexible air brake pipe have been specified – Ralph is a big locomotive and railway specification parts are an important part of making sure he’s as safe as possible in operation when modifications are made.
26th November 2025
The fireman’s cab side has now been measured and cut for the recess that houses the number and maker’s plates. The recess is already manufactured and on hand.
13th November 2025
Livery testing to ascertain what is needed to get the desired finish has started, with the front sand box lids receiving their first coat of paint.
3rd November 2025
Ralph’s new front and rear pilots and new draw gear/coupler assemblies are now complete and ready to go to be media blasted and painted prior to dispatch to the trust’s workshops in Sheffield. These are the first major new parts to be fitted to the ’91 so we are very excited to see them installed. They will also restore the original look of the front of the locomotive that was lost when RRL Grindrod converted it to Cape gauge.
8th October 2025
Progress continues on Ralph’s new pilots assemblies and drawgear at Boston Lodge works.
22nd September 2025
Assembly work has started on Ralph’s new pilots. These photos show the couplers returned to their old lower height.
29th August 2025
The MU mount plate from the front pilot is finally in its last coat of red paint. The next task is to decide on a suitable finish for the inside of the coupler light shade (on the right side of the part in this photo).
26th August 2025
The kit of parts for Ralph’s new pilots has arrived and is awaiting assembly. Some cab parts are back from the blasters but others will need to be returned for a second blasting as they are not yet clean enough.
21st July 2025
More of the cab interior is stripped and the parts are ready to go for blasting. A missing cab door striker has turned up in a pile of dirt behind the cab. It’s now cleaned up and painted so it can go into storage pending reassembly. The MU socket cover and uncoupling bar brackets from the front pilot have also had another coat of paint.
13th July 2025
Stripping the interior of the cab continues. The left side is now prepped for the reinstallation of the plate recess and several more internal panels are out, along with the wheelslip control computer and cooker.
01st April 2025
Welding is now complete on the driver’s side of Ralph’s cab. The number plate recess is dressed and ready for paint, and a large gash in the cab roof that had previously been covered in sealant is now welded and dressed.
18th March 2025
The gauging studies for Ralph are now complete, along with the profile drawings for the replacement pilot parts. These have gone out for quotes already.
12th March 2025
The design for Ralph’s new pilots and drawgear is pretty much finished. The next step is drawing the cutting diagrams and obtaining quotes for the manufacture of the parts. Installation will be handled in our own workshop.
08th March 2025
The first test fit of the cabside number plates happened today and they look amazing!
04th March 2025
The first of the recessed number plate panels is installed in Ralph’s cab side and looks amazing. I can’t wait to see it with the plates on.
02nd March 2025
Two of the eight bolts that hold the short hood down were seized when it was removed and had to be cut off to release it. With the new three phase supply finally installed in the workshop it was finally time to try removing them using the welder. One came out without too much fuss, the other is being more reluctant. The thread has picked up inside the steel support block causing the bolt to snap several times. Another attempt will be made soon.
28th February 2025
Metal work has started on Ralph’s cab, with both sides measured up for the number plate recesses and the driver’s side cut out ready for welding.
27th February 2025
Ralph’s horns, front lamp brackets and upper front short hood hand rail are now all in final finish paint and await reinstalling. The front AAR multiple unit cover and the front coupler release handle brackets are now also painted in the correct shade of red. These will need another coat or two to get to final finish. The little pagoda shaped housing on the M.U. mount is for the coupling light which illuminates the draw gear at night. This had long since gone missing but will be reinstated as part of the restoration.
24th February 2025
It has been decided to replace Ralph’s pilots at both ends. The originals are heavily pitted and badly bent. The front one has suffered from numerous minor collisions through the locomotive’s life and has mostly been replaced before in sections. When it was prepared for use with Grindrod an AAR (American Association of Raillroads) drag box was fitted which is too high and of a design not suited to Ffestiniog Railway type chopper couplings. Replacing the pilots will allow for complete replacement without it looking messy.
PROJECT Gallery
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