Our blog concerns the story of the rebuilding of our polish built locomotive ‘Naklo’. Kindly funded by The Power to Change Community Business Fund, the locomotive’s main frames and tender are being rebuilt in our own workshops in Alston. Meanwhile the all important boiler, was rebuilt by TRS Boiler Makers in Derbyshire.
Our story starts in August 2018 once the boiler had been removed and shipped off as a template for a new boiler, work started on stripping down the locomotive to its component parts so its condition could be assessed and plans made for the necessary repairs and refurbishments.
Back at Alston the stripping of the main frames is complete and the frames now stand on a bogie flat for assessment and further restoration.
Moving into November 2018 , the frames have been needle gunned and new metal has replaced areas where corrosion has taken hold.
Christmas time brought running of the STR Santa trains and the Christmas break. In January 2019 reassembly of the Naklo’s frames has begun, with the cylinders now back on the frames. Work has started on the tender. the severe corrosion of the tender tank means this will need to be replaced. As we shall see in the future corrosion of the tender frames will also need a lot of corrective fabrication. As originally acquired from Poland Naklo had side tanks, in an earlier rebuild these were removed and water was carried in a tank on the tender. As this reduced the adhesive weight of the locomotive, the tanks are being re-instated and the new tender will now have spaces for water, fuel and a battery compressor compartment for the train’s air brakes.
Towards the end of January fabrication work is the main activity with Naklo’s side tanks being made as well as the new tender body.#
Early February was a very important day for the Naklo project, the completed boiler was delivered from TRS Boilermakers in Melbourne Derbyshire.
After the excitement of the arrival of the boiler fabrication work continues. The three photos that follow show the tender body and components being fabricated
Fast forward to March 2019, the boiler has been mounted on the mainframes, the new side tanks are finished, have been test fitted and temporarily removed to allow access for other work. The smokebox has been fitted, a new smokebox door and baffle has been skillfully fabricated and turned on a lathe to ensure a parallel fit between the smokebox and door. The ends of the tender frame have produced some surprises with double thicknesses of plate, that have provided a harborage for moisture and consequently rust!
Work has been going on to create the steam inlet and exhaust exhaust pipework which takes steam to and from the cylinders. Curved exhaust pipes have been carefully fabricated from small sections of pipework to provide a route for low pressure exhaust steam from the cylinders to the blastpipe. A hole in the blastpipe has been repaired and pressure resistant pipework has been fabricated to take boiler pressure steam from the boiler to the cylinders.
June sees the tender body nearing completion
July – sees work focusing on wheels, axles and axleboxes.
August – Work starts on the cab.
September – The tender gets ready for its brake compressor to be fitted and is mounted on its wheels. Naklo’s cab heads towards completion. Naklo’s driving wheels visit the lathe to have thier tyres turned.
By the 25th of October came the time to start fitting Naklo’s driving wheels. The boiler, tanks, and cab were removed and the chassis turned upside down to allow the driving wheels to be fitted to the locomotive’s main frames.
2nd November 2019
22nd November 2019
23rd November 2019
Whilst Naklo is stripped down there is an opportunity to see some of the parts of the engine always hidden from view.
Work is coming to a close on the brake compressor and battery pack installation in Naklo’s tender.
28th November 2019
29th November 2019
06 December 2019
Outside the workshop in Alston today, there was much activity making preparations for the operation of STR’s first weekend of Santa Specials. Inside the workshop, progress was also being made, with the first pair of Naklo’s driving wheels, now fitted to the locomotive’s frames.
There has been progress with the tender, air valves to feed the flexible brake pipes between the tender and the train have been fitted. These valves connect to the original tender brake piping. The tender’s compressor/battery pack doors have been trial fitted with opening handles, they were being welded in place this afternoon.
9th December 2019
Today work continues on Naklo’s tender and fitting the centre flangeless driving wheel to the locomotive’s main frames.
18th of December 2019
Naklo gets its driving wheels fitted and preparations are being made to fit the springs and spring hangers.
Work continues on the tender with a second train brake air reservoir fitted and some plating work on the front upper corners of the tender.
20th December 2019
On the Friday before the STR’s 3rd Santa weekend, work continues on Naklo’s tender and locomotive main frames.
On Naklo’s main frames the locomotive’s springs and suspension components continue to be assembled.
9th of January 2020
Into 2020 and here’s our new year update on the progress with Naklo’s rebuild.
Locomotive main frames
24th of January 2020
Naklo is back on its wheels and preparations are being made to return the boiler to the frames. We’re making good progress on the air brake pipework in the tender.
The frames didn’t have to wait long for the boiler, your webmaster was surprised to get an e-mail this afternoon, with two shots of the Naklo’s boiler back in the frames. We’ll done to Steve and Chris our staff engineers at Alston workshops.
6th of February 2020
With the boiler back in the frames, we’re beginning to fit the boiler with a multitude of pipework and boiler fittings, that are needed to gradually turn it from a rolling chassis into a locomotive.
Clack valves and thier boiler mountings
Boiler fittings The workshop was busy today with preparatory work on boiler fittings.
14th of February 2020
Fitting the regulator valve
As I’m sure many readers will know the regulator valve on a steam engine controls the steam, that flows from the boiler to the cylinders to turn the wheels via the connecting + coupling rods and drive the locomotive.
Fitting the regulator valve is not a straightforward job, to quote our engineer Steve Race, “it’s the engineering equivalent of a complex medical procedure”. The regulator valve is mounted within the very tight confines of the dome, it’s operated by a long curved rod attached to the top of the valve, actuated by a crank mounted on the regulator shaft which is mounted inside the boiler just above the boiler tubes and operated by an external lever mounted on the backhead of the boiler. The long and heavy regulator shaft enters the boiler through a stuffing box on the boiler backhead. The most difficult task is to ‘lasso’ the end of the regulator shaft with a rope so it can be held in place, whilst the crank and rod that operate the regulator valve are attached, to complete the assembly.
In the photos that follow we enter the tight and compact area of the steam dome, only seen as times like this when a new boiler is being commissioned.
Lets get our bearings and see where everything is situated before we get down to details
21st of February
Work has started on the coupling rods and thier bearings. Each coupling rod has a vertical hinge pin that allows the rods to move to accommodate the vertical movement of the locomotive on its 3 axles. Naklo’s coupling rods overlap by half a rods thickness at the point where the rod is hinged. The hinge pin bearing needed replacing. In the shot that follows, we see the hole in a coupling rod in which the bearing is mounted. The bearings were seized in the rod and have had to be cut out. Another progress report next week.
5th of March
Sorry, there was a bit more than a weeks gap between updates. Re-assembly of Naklo continues, the firebars are in the firebox, the first coupling rod is being fitted, the damper controls are being assembled, a pillar for the handbrake has been made, the exhaust and inlet pipework is almost complete and the smokebox has had a smart coat of heat resistant black paint!
6th March 2020
Work on coupling rods continues.
7th of March 2020
Back in Alston again, today sees the rear right hand coupling rod in place and the re-assembly of the smokebox pipework almost complete.
11th March 2020
14th March 2020
17th March 2020
4th of April 2020
South Tynedale Railway is following government advice concerning the current Covid-19 virus, consequently restoration work on Naklo is suspended until further notice. We will bring you news of any further work on the locomotive as soon as it becomes known.
20th of May 2020
Good news, restoration work on Naklo re-started in early May, where Steven Race has been back at work for 3 days a week. The photos were taken on Tuesday 19th of May, they show the excellent progress being made on the rebuilding of Naklo’s pistons, slide bars and valve motion.
Pistons, rods, die blocks and cylinder drain cock rods. In this photo we see both Naklo’s pistons and rods which have been machined ready to receive the piston rings which have been ordered from an external supplier. On the left hand piston is one of two die blocks made recently, they fit in the expansion links of the Walschaerts valve gear. The thin rods with the cut outs in them, are the two new cylinder drain cock actuating rods. For comparison, one of the worn originals sits at the bottom of the shot.
Slide Bars The slide bars for the crossheads have now been machined. The before and after shot below, shows an un-machined rod on the left and a newly machine rod on the right.
The shot below shows one of the old worn crosshead slipper bearings. Steve made a new pattern for these, which has been sent to the William Lane foundry in Middlesbrough for 4 bronze new slipper bearings to be cast, which will be machined and fitted when the castings return from the foundry.
Valve Rods These rods actuate the slide valves in the valve chests. The shot below shows one of the rods propped up against the loco. The threaded section at the bottom end of the rod is where it is connected to the slide valves.
Expansion link with die block plus slide bar. In the photograph below we see one of the new die blocks sitting in the expansion link, with one of the machined slide bars propped up beside it.
General view on Naklo Here’s a general view of Naklo as of Tuesday 19th of May.
More updates to follow soon.
28th of May 2020
Work continues on Naklo’s valve gear, connecting rods and pistons. In the ‘old bits that need replacing’ department here are two piston rings now too worn to reuse, new replacements are on order and are expected soon.
The valve stem guides have been machined an fitted on both cylinders.
New Neck Rings, the bearings that support the valve rod at the rear of the cylinder, have been produced to fit the valve rods that have been in turn, machined, to remove any wear where the rod passes through the gland, before it enters the valve chest.
Lubrication grease nipples have been fitted to Naklo’s suspension.
Awaiting their turn in the refurbishment queue are rear cylinder covers with crosshead bar supports and two crossheads sitting on the sack barrow below.
6th July 2020
Cylinder covers – The rear cylinder covers which also support the end of Naklo’s single slide bar have now been fitted.
Combined clack/stop valve – These original valves, which allow water to enter the boiler from Naklo’s injectors, have been refurbished and now fitted to the both sides of the boiler to take the feed from the locomotive’s two live steam injectors.
Piston Rings – The 4 new rings have been delivered, here’s a shot of an old ring on the left and sitting on top of a machined piston, two new rings in the queue to be fitted.
8th – 10th July 2020
Naklo gets its pistons with new piston rings fitted.
Steve Race our engineer at STR started fitting new piston rings to Naklo’s piston this week. First task was to get the shiny new and very stiff rings on to the piston. The rings are first carefully opened up and using lots of small pieces of hacksaw blade eased over the head of the piston and into the two slots in the piston head which have been carefully machined to ensure the rings are a sung fit, and able to withstand the forces acting on the piston.
Removing the crosshead drop link pin 10th June 2020
Having installed the pistons Steve’s next step was to work on the crosshead drop link. The diagram below, will help our visitors which bits of Naklo’s Walschaert’s valve gear, that’s being described
The key components of Walschaerts Valve Gear: this diagram has piston valves, however, Naklo has slide valves.
Eccentric crank (UK: return crank)
Crosshead arm (UK Drop link)
Valve stem guide
Another focus for today was removal of the large pins that connects the crosshead drop link, (No.9 in the diagram above) to the union link an thus onwards to the valves via the combination link. The pin in question was tight press fit in the crosshead casting, the shot above, of the part of the crosshead that houses the pin shows signs of the heat, that had to be applied to help release the pin using our hydraulic press. Looking at the drop link before we removed the pin the alignment of the pin didn’t look promising.
13th -18th June 2020
With the crosshead drop links sorted, the next job was to start assembling the RH side crosshead. Here we see the start of the assembly process, with the piston rod mounted in the crosshead supported by a jack and a block of wood.
The top and bottom crosshead slipper bearings that support the crosshead as it slides on Naklo’s single slide bar arrived back from William Lane Foundry in Middlesborough. Below we see a shot of – top – the pattern for the slipper bearing casting middle – the the raw Phosphor Bronze PB2 casting before machining and lastly one of the original worn bearings, all sitting on Naklo’s footplating.
The timely arrival of the castings meant that machining operations could get started on the slipper bearings. Here we one of the castings being machined on the milling machine.
Here’s a close up shot of the milling cutter doing its work.