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Overhaul, Chemical blacking and Detailing of..
Original 1:148 scale British Farish N gauge rebuilt pacific 35028 `Clan Line'
This locomotive was owned by John Burtenshaw at the time of its first overhaul and chemical blacking.
It is now owned and operated by the Stoneybridge Railway allocated to the Stoneybridge West exhibition layout.
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Seen here in `As New' condition, N gauge Graham Farish No.1513 pacific class locomotive. Rebuilt merchant navy `Clan Line' 35028 looking very smart in B.R. lined Green. The locomotive lining, nameplates and emblem on the tender sides are excellently reproduced, the text on nameplates and tender emblems can actually be read with the aid of a good magnifying glass. |
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35028 `Clan Line' ready to run, `straight out of the box' with shiny new BFB (Bulleid-Firth-Brown) wheelset and outside valve gear, AARGH! The overscale wheel thickness on these models is made more obvious and thus appear larger due to the shiny nickel-silver finish. This is one thing I personally dislike about most Ngauge locos, but the dreaded shiny wheels will be attended to during overhaul :-) |
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35028 placed upside down in a locomotive service cradle for chassis removal. By leaving the loco body in the cradle it can be safely stored away until required for refitting later. This ensures the bodywork does not come to harm whilst the rest of the locomotive is being worked on. Care must be taken to avoid damage to the motion gear components when removing the chassis from the body. Do not pick up the chassis unit by holding the motion gear of drive rods as they are not easy to repair when bent or damaged.(/TD> |
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Motor/Chassis assembly removed from locomotive body. The wire on the left goes from the motor in the locomotive through the cab and through the `coal hole' on the front of the tender, it is disconnected by de-soldering it from its connection in the tender. leading and trailing `pony trucks' have also been removed. You can see the turned brass worm gear on the leading end of the motor armature just above the center driving wheel, the rear end of the armature has the commutator and brushes arranged so one brush is in the lower (Cast metal) half of the chassis, the other brush is in the upper (moulded plastic) section. The upper plastic section of chassis also houses the magnet, which is flanked by a metal plate on each side of the chassis assembly, these plates are of a high magnetic permeability and are utilised to extend and direct the North and South polarised magnetic fields from the magnet around the motor armature windings. |
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Motor/Chassis assembly on its side with `keeper plate' removed. the two short screws hold the keeper plate to the chassis, the long screw passes upwards through the keeper plate, pickups and chassis into the body shell holding the chassis components firmly in place. |
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`wheel wiper' type electrical pickups removed from chassis/motor assembly with plastic insulating seperator. This is set aside with its locating screw as shown to ensure correct orientation of components when re-assembling the chassis. The locating screw passes through the chassis and is fixed with a nut on top of the chassis/motor unit. This screw is also used as the electrical feed from the pickup `wiper plate' to the motor and has a fine wire looped round the top end of the screw held firmly with the nut. |
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Wheels and valve gear assembly removed from chassis. This is a delicate operation and must be approached with great care. The ends of the uppermost rods (seen above and between the leading and center driving wheels) requires very carefull removal from two fine plastic `arms' that protrude from the sides of the chassis assembly. |
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BFB wheelset and valve gear washed, de-greased and brushed up with a soft brass bristled brush ready for chemical blacking. |
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Complete wheelset including loco driving wheels/valvegear assembly, leading/trailing wheels, tender wheels and tender drawbar cleaned, de-greased and brushed up ready for chemical blacking. |
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Driving wheels and motion gear after the first stage of chemical blacking, `brushed up' in readiness for the second process. The first stage consisted of painting on the blacking chemicals with a fine brush ensuring that only the areas I want to black were affected, I have missed a few bits but they will get touched in during the second part of the hand blacking process. |
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Care was taken to avoid chemically blacking the `slide bars' as these are one of the very few parts of a locomotives motion components that should be shiny! Next time You see a photo of a steam engine (or even better a real live loco) take a carefull look at the motion gear, drive and coupling rods. On some preserved locomotives the outside motion gear and rods will be kept clean and often polished but the slide bars and cylinder plunger rod will be some of the very few shiny bits of a steam locomotive on active duty, most of the other shiny bits would be in the cab!. |
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The tender wheels were `double dipped' (by full immersion) cleaned and are seen here refitted to the tender chassis. The middle carrying axle of the tender is not used for current collection so the center `axle slot' in the chassis has been slightly deepened and two lead weights have been placed above the outer axles. These modifications help to prevent the tender from `flying' when running tender first ensuring good current collection and preventing derailments, as an added bunus the weight stops the tender `jumping' when coupling onto a train. |
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Complete pacific 4-6-2 + tender wheelset after first chemical blacking process. The driving wheels will undergo a second process of blacking by hand (with a fine brush) after which they will be cleaned up and refitted to the Farish chassis block for final touch-up and detailing. |
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Clan Line's `BFB' driving wheels and outside valve gear after a second chemical blacking process. The driving wheels were blacked `by hand' using cotton buds and a fine brush to selectively place the blacking chemicals leaving the backs of the wheels and axle untreated, the wheelbacks were polished before chassis assembly to reduce friction between the wheels and `wheel wipers' used for traction power collection. |
Rebuilding the locomotive is mostly a simple matter of reversing the stripping down process, taking care to route the wire from the top of the motor out of the loco through the cab, in through the front of the tender body and carefully resolder onto the contact tag on the tender chassis assembly. The tender drawbar must be clean at both loco and tender ends as it is also used to carry current from the tender pickups.
The Rebuilt,
Rebuilt Merchant Navy Locomotive.
| All wheels and motion gear components have been blackened using a selenium dioxide solution. The leading and trailing bogie wheels were `dipped' as normal but the driving wheels and motion gear components were all treated with chemicals applied by hand with a fine artists paintbrush, this allowed me to selectively leave the slide bars shiny and inner faces of the driving wheels untreated. A few small details have also been added, The front bufferbeam now has a `Scalelink' 2mm scale hook and screw coupling fitted, A few grammes of lead have been fitted inside the tender to stop it `flying'. There is also a fireman on the footplate complete with shovel. | |
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The completed loco, rebuilt with blackened wheels, conrods & outside valve gear giving the model a much more prototypical appearance. Chemical blacking also helps to reduce the percieved size of the wheel flanges which were very noticeable before blacking especially on the leading bogie wheels. The fireman's blue jacket can be just seen through the cab windows. |
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Released back into traffic, 35028 `CLANLINE' being turned at the old Stoneybridge MPD in preparation to leave on her long journey home. |
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02 Feb 2002, Clanline back in traffic on the Stoneybridge Railway, allocated to Stoneybridge West shed after heavy general overhaul. Faults found on the loco included; Bent rear and center driving axles, I had lots of fun bending them back to almost straight, She still has a wobble but a lot less pronounced than before. The armature and brush holders were clogged with dust and have have been cleaned, the drive train had developed a tight spot and failed to run freely, this was stripped, cleaned, re-greased and rebuilt. The tender has also been modified, being completely stripped down, cleaned and re-assembled. During assembly of the tender I added a few more grammes of lead to the rear of the tender chassis to stop the tender riding high over check rails and ultimately derailing when running back. The tender's rear coupler pocket was packed up with a layer of thin plastic to stop the coupling from `dropping away' and uncoupling when least required. All traction current pickups on loco and tender have been cleaned, degreased and re-sprung with the backs and tops of the wheel flanges being cleaned and degreased for optimum traction current collection. All that remains to be done on this loco is a little more detailing of the bufferbeams and area below the cab floor followed by a very light all over weathering, as Stoneybridge West's Top link loco it would be kept in fine fettle by enginemen, firemen and cleaners with the shedmaster giving an appreciative nod when he is satisfied that Clanline is ready for duty. |
Copyright Notes
