This Blog describes the ongoing development of a 16mm scale 45mm gauge garden railway situated in the North West of England, UK from 2004 to the present day.
An almost unbroken spell of sunshine for around three weeks has led to quite a few running sessions and more than a few spells of continuous running while we've had barbecues or simply lazed in the garden. However, I have also taken the opportunity to finish off a couple of jobs and spend some time trying to sort out others.
Loco No. 4 Bulkeley
As mentioned in Progress Report 46, I have been working steadily on scratchbuilding a body for loco No. 4 - Bulkeley, based loosely on the Southwold Railway No. 4, Wenhaston. This was my first venture into building a steam outline loco but I used the skills I had acquired in building the Fowler diesel and rolling stock such the the cattle wagons to construct her largely from plasticard (see How I constructed an 0-6-2T Manning Wardle locomotive). The build was fairly straightforward though I did run into an unforeseen problem when she developed wheelspin on what seemed like insignificant gradients. I eventually tracked this down to the lower end of the bracket supporting the valve gear which was rubbing on the track. This was solved through the addition of an upper support bracket.
For a while, I was uncertain as to the livery of the original Southwold Railway loco - there seemed to be some ambiguity in the books on the SR which suggested she was lined out in light and dark green and yet the photos of the loco I had unearthed show no evidence of lining. After making an enquiry with the Southwold Railway Trust, I discovered that when delivered from Manning Wardle, she was lined.................
....... but when she entered service she was painted in plain dark green livery which she retained throughout her working life. However, towards the end of her life, her livery faded and her works livery started showing through.
My model has now entered service on the Peckforton Light Railway and for the moment she is sporting the line's livery of Brunswick Green (or in her case, Rover Brooklands Green from a Halford's rattle can aerosol). I am trying to decide whether to line her out in gold as with the line's other locos or whether to leave her unlined as a homage to her Southwold origins. You'll notice that I've positioned the loco's number beneath the nameplate as in her Southwold days.
She also has acquired a bespoke driver, made from oven hardening clay. I wanted to represent a driver or fireman passing over a token or just leaning out to watch the loco's motion. He's reasonably detailed though it looks as if his face has met with an unfortunate collision somewhere down the line.
The loco was my first real venture into battery power and after a few teething troubles I am steadily being won over to this form of power. However, I am also upgrading my DCC powered fleet (see below) to improve their reliability.
Adding DIY Power buffers to DCC locos
As all my track-powered DCC locos are designed around LGB 0-4-0 motor blocks it's inevitable that they experience problems when running slowly over the plastic frogs of pointwork. Last year, I invested in a Massoth Power buffer and added this to one of the locos to evaluate its effectiveness (see Progress Report 37). I was extremely pleased with the outcome and vowed I would equip all my locos with one. Despite its relatively low cost (under £25), having retired, funds are not always readily available and so when I came across an article in the French railway modelling magazine, Voie Libre, explaining how a modeller had added his own power buffers to his 0n30 locos, I researched the subject and found out how it can be achieved for as little as £2.50 per loco (see How I added DIY Power Buffers to my Locos).
All my track powered locos are now equipped with power-buffers and, because I was hard-pressed to find a suitable location for the buffer in my Fowler diesel, I adopted the technique used in the original article and added the capacitor to the footplate to represent an air cylinder.
Working on the gearbox of the IP Engineering diesel loco
I spent a day or so trying to build my own gearbox to replace the one supplied with the IP Engineering diesel kit, Jessie (see How I constructed a battery powered diesel from a kit). The gearbox as supplied used plastic gears and after only a very brief period of test running these became stripped of their teeth. I bought what I am hoping are more substantial metal gears from Cambrian Models but found that their 20:1 gears are not a direct replacement as the overall dimensions differ. I therefore attempted to construct my own gear housing from brass.
Whilst this worked to some extent, I found that as soon as even a small load was placed on the loco, the gears slipped (though only in reverse, the mesh was fine as long as the loco only travelled forwards). I am now attempting to construct a more reliable gearbox, building on the knowledge I've acquired so far and drawing on the expertise of a friend who has more metal working experience.
Improving the keyfob control on the railbus
After some interesting discussions on the G Scale Central forum about the merits of using a cheap 12v LCD dimmer unit to control a motor.
It seems that the unreliability which I had encountered over the speed control of the motor could be greatly improved through the simple addition of a diode across the output connections - see the excellent online article by Dave Bodnar.
I have disassembled my railbus (see How I constructed a railbus) and have duly wired in the requisite diode.
At the same time I decided to replace the array of AA battery boxes I had used previously with a single 12v Li-ion battery pack which would take up considerably less room. Unfortunately, the pack which I had bought from China via a well known online auction site ceased to function and so I have been unable to test my newly adapted control board. Furthermore, I am growing increasingly concerned with the IP Engineering gearbox which at 16:1 does not provide sufficient torque to power both cars and I am assuming will ultimately strip its gears (see above). I am therefore investigating an alternative approach to powering this vehicle and will post an update when I feel I have made some progress.
More running sessions
As indicated above, the weather has provided me with plenty of opportunity to run trains. I have continued to use my original freight handling computer program (see Computerised freight operation) but have discovered that the freebie software I used to create the freight handling program will not work on Windows 7. I have fortunately found another programming environment which is not only free, it will create standalone programs to run on PC, Mac, tablets and smartphones (Livecode - which is based on the original Mac program - Hypercard). Once I have completed the re-programming I am hoping to be able to distribute various versions for others to use.
In the meantime, here is a small taste of some of the moments drawn from recent operating sessions.
The Down mid morning passenger approaching Bickerton
No. 2 Beeston on the afternoon Up passenger crosses the River Gowy between Peckforton and Beeston Castle
The daily pickup goods arrives at Bickerton with Hunslet No. 3 Bickerton
The pickup goods departs Bickerton on its way up the line towards Bulkeley
Shunting at Bulkeley
No. 3 emerges from the Copper Mine branch running light after delivering a fuel tank wagon
The Up pick-up goods approaching Peckforton where it will cross the Down afternoon passenger
Now I have managed to sort out the slow running of the locos (see above), I take great delight in relaxing from time to time in a strategically placed garden chair as I watch each train slowly threading its way through the undergrowth from station to station. There is something very satisfying about seeing a train which I have created going about its business.
The things I enjoy most about my railway are slow running and shunting operations. However, as most of my locos are short wheelbase 0-4-0s I often get very frustrated when they stall or stumble on minute patches of dirt on the rail or when they encounter the plastic frogs of pointwork. As shunting requires a lot of slow running over pointwork, there are occasions when I have to bite my lip, mutter and count rapidly to 10.
About a year ago I fitted a Massoth Power Buffer to one of my locos (see Progress Report 37) and have been very pleased with the results. Although the power buffers are less than £25, having now retired, I felt the outlay to equip the rest of my loco fleet was something I would have to postpone until funds improved. All that changed when I came across an article in a copy of Voie Libre explaining (in French) how someone had added his own power buffer. A quick trawl through the internet unearthed an entry on the Massoth Users' forum by one of their technical staff explaining how a simple DIY buffer could be added to one of their decoders. As Massoth manufacture decoders for LGB, the same process can be carried out on their LGB's 'own brand' decoders.
Once the equipment has been purchased, the process is actually quite straightforward and took me only an hour (though on some locos, it took a little longer to create the space needed to accommodate the additional circuitry).
Before fitting the buffer, the decoder's CV29 has to be reprogrammed to disable analogue control. Without this, the power buffer would confuse the decoder into believing it was under analogue control and hence would ignore DCC commands.
The programming module was inserted LGB (55015) Universal Remote:
This was then wired up - the yellow and green wires into the transformer and the brown and white leads to the decoder via a piece of rail which I reserve for programming purposes.
CV 29 was then programmed by following these steps:
1 - The loco was placed on the track and the transformer was powered up
2 - The letter C appeared on the LED display on the handset
3 - 29 was then entered on the remote's keyboard
3 - 0 was then entered into the keyboard (this tells CV29 to accept 14 steps in digital only)
4 - The right arrow was pressed on the remote
5 - Provided everything is OK, the letter C should appear on the display
For each buffer, I bought three electronic items from my local Maplin store:
The diode and the resistor were soldered together in parallel.
These were then soldered to the positive lead of the capacitor and a plain (red) wire was soldered to the the other end of the two components. Another (grey) wire was soldered to the negative lead of the capacitor. The whole assembly was then shrouded in insulating tape to help avoid accidental short circuits.
Connectors were soldered to the other ends of the wires and these were then pushed on to the D+ and D- tags on the Massoth L decoder (this is identical to the LGB 55021 decoder).
The decoder and buffer were then inserted back into the loco and the loco re-assembled.
Yes, it really was that simple, but the proof of the pudding ..............
For me the advantages of this system far outweigh the disadvantages. The loco won't run on an analogue powered railway and the the CVs (including the loco channel number) cannot be programmed unless the power buffer is disconnected. However, as it is connected to the decoder's power feed tags it's a fairly easy process to remove the buffer should the decoder need to be reprogrammed. Alternatively, a switch could be wired into the feed to the buffer should I want to more easily disable the buffer.
I have always had considerable interest in the Southwold Railway, having lived for my formative years in East Anglia. For me, the Southwold, together with the Welshpool and Llanfair, epitomise what narrow gauge railways in the UK are about - serving rural communities, carrying goods and passengers between fairly remote locations, and being somewhat idiosyncratic in their nature and operation.
The Southwold locomotives were also quite individual; not just the original 1879 2-4-0 and 1893 2-4-2 Sharp Stewarts but the more powerful 0-6-2 Manning Wardle, Wenhaston, which joined the line in 1914 to meet an anticipated increased demand for goods traffic generated by the opening of the harbour branch (the traffic never materialised).
And so, having acquired a secondhand LGB Zillertalbahn 0-6-2 U-Class locomotive a few years ago (see Progress Report 9), .....
...... I promised myself that one day I would use this chassis as the basis for the construction of a loco based on Wenhaston. That time has now arrived! As with most things in life, though, now I've actually made the model, I now know how I should have gone about the job - if I knew then what I know now and all that. Hopefully, though, if you want to follow in my footsteps you might benefit from my mistakes and learning curve.
My first task was to strip down the Zillertalbahn loco to its bare chassis. The bodywork was easily detached from the chassis; firstly by unscrewing the chimney, taking out the front coupling, ..........
....... removing the screws which attached the cab to the chassis and detaching what I assume is the 'brass' safety valve from the front of the cab.
The cab could now be separated from the chassis.
To detach the front end of the loco body, two screws were removed from just in front of the cab and the body was then slid forward to detach the lug at the front.
After removing the Massoth DCC decoder which I had installed soon after acquiring the loco, I was then able to size-up the chassis.
The trailing bogie was removed by unscrewing the two screws on the retaining plate. The bogie was set aside to be used in the completed loco but the pivot arm will need to be reduced in length.
The cab footplate was then carefully excised from the main chassis with a razor saw, leaving me with the main chassis. The wheels are the correct size for a 15mm:1ft scale model but, although the axle centres are about right on the leading and centre driving wheels, the wheel spacing is too narrow for the trailing driving wheels. However, as correcting this would require a wholesale rebuild of the chassis, I decided this was a detail which I could live with.
All my locos are representations 'inspired' by their prototypes and so
this will be the same. I was disappointed to see that the motor housing
actually rises 15mm above the footplate and as this projects into the
space above the leading driving wheel, I will be unable to model fresh air between the chassis and the boiler. Another compromise.
I next stripped down the chassis to remove any unnecessary wiring for the track pick-up system. On this U-class, pick-up was via carbon rods bearing on the backs of the driving wheels. An arrangement of brass contact strips inside the frames carries the current from the back of the pick-ups to a couple of bus-bars which run the length of the chassis.
All this paraphernalia was removed .......
..... and the chassis loosely reassembled for painting, later.
Having measured-up the chassis and compared it with the plans for Wenhaston found in the Middleton Press Branchline to Southwold (Mitchell & Smith, 1984) and in the March 1987 edition of Model Railway Constructor, I marked-out and shaped the rear footplate from a piece of 2mm thick (80 thou) plasticard.
I next cut-out the sides for the water tanks from 2mm plasticard.
To these were glued the ends, top and bottom of the tanks which were cut from a mix of 2mm and 1.5mm thick (60thou) plasticard - largely because I was constructing this model whilst on holiday abroad and had brought only a limited supply of 2mm plasticard with me.
I removed a section from the lower part of the inside edge of the tanks in anticipation of filling these with lead weights.
The curved edge of the tanks were built-up from scraps of plasticard and filler, sanded down with a needle file and sandpaper.
This will be fine-tuned later after a couple of coats of primer. The tanks were then glued to the footplate.
After hunting around the bits-drawer and garage at home for some suitably sized bits of cylindrical plastic, I found the diameter of a tube of silicon sealant to be spot-on for the smokebox. A piece of this was then cut to size .......
....... and glued between two pieces of 1.5mm thick plasticard, suitably shaped.After trying a few different types of adhesives, I opted for clear UHU to fix these parts together. The sealant tube is made from some sort of oily plastic which does not seem to accept most glues - presumably this is why this plastic is used for packaging sealants.
As with the curved section of the sidetanks, the concave curve where the smokebox meets the footplate was fashioned from offcuts of plasticard and dollops of filler, filed and sanded to shape.
The front and rear of the cab were then cut from 1.5mm plasticard.
The sides were also cut out (from 2mm thick plasticard for rigidity), and the cab was then attached to the footplate.
To provide additional support for the rear of the bunker, an additional piece of 2mm plasticard was shaped and glued to the centre of the cab rear.
The front half of the firebox was tackled next. A couple of pieces of 2mm thick plasticard were shaped for the front and rear of the firebox .......
and a piece of 1mm thick plasticard glued over it. This assembly was then glued into place between the side tanks.
I was not too happy with how this looked and so another piece of 1mm plasticard was glued over the top and the space left between the two layers was filled, filed and sanded. As I was working from a drawing and a couple of indistinct photos, I decided to use modellers' licence over the exact profile of the firebox. With the restricted room inside the body, I needed as much additional height as I could manage. Yet another compromise.
The leading edge was then rounded off with a needle file and smoothed off with fine sandpaper. The rear half of the firebox was constructed next in a similar way. I decided to make this slightly deeper than the prototype to accommodate the radio control receiver and motor controller.
This was then glued into place in the cab.
I like the roofs of my locos to be removable to facilitate detailing and painting. A framework of 2mm plasticard was made to be a snug fit inside the top of the cab. I tend to glue items like this together with Superglue as it dries more quickly than solvent adhesives which means I can more readily move on to the next stage.
To this was attached a piece of 1mm plasticard (held in place with clothes pegs until the glue set).
The roof was then test-fitted......
...... before some strips of 1mm wide, 1mm thick plasticard were added to the outer edges of the roof to represent rain-strips.
Next,the sandboxes were constructed. The sides were constructed first from 1.5mm plasticard and then, when the glue had set, oversized tops and bottoms were added.
Once the glue had set, the tops and bottoms were trimmed to size and the whole thing lightly sanded. I've found from experience that this is a more accurate way of ensuring the tops and bottoms actually fit the sides. The same method was used for the toolbox which was attached to the footplate beside the smokebox. One source suggests that the toolbox was needed because when the loco was delivered it was found to be underweight over the leading driving wheels.
The outer frame of the toolbox was then added from 4.5mm wide strips of 1mm thick plasticard.
The inside section of the coal bunker was tackled next. Having no details of its appearance, I assumed it would be similar to other tank locos. A piece of 2mm thick plasticard was cut to size and then a 14mm x 14mm hatch was cut into the middle of the bottom edge. Two strips of 1mm square plasticard were then glued vertically either side of the hatch and a 16mm square hatch cover was cut from 1mm plasticard.
Two 2mm x 1mm strips of plasticard were then glued on top of the strips to provide a grooved slideway for the hatch cover.......
....... which was slotted in to be allowed to slide up and down.
On returning from holiday, I had a slight change of plan. I removed the rear of the cab so I could add some detail to the backhead of the firebox. A set of whitemetal detailing parts was obtained from GRS (Garden Railway Specialists) and these were affixed roughly where I felt they would have been on the original loco.
Next, the chimney, tank fillers, safety valves and whistle were attached to the top of the smokebox and firebox. These again were provided by GRS as whitemetal castings. I was stumped when it came to finding a dome, however. Nothing which GRS had available was suitable, but a trip to the local supermarket resulted in the purchase of a bottle of after-sun cream with an interesting-looking domed cap.
This proved to be more or less the right size - but actually would have been entirely accurate had I been constructing the model in 16mm scale(!). The cap was shaped to fit the boiler, glued on and liberal amounts of filler used to merge the dome into the curve of the boiler. The was smoothed down with various needle files and increasingly smoother grades of emery paper.
As I didn't take the chassis or the battery with me on holiday (we took
cabin baggage only), I had to leave the shaping of the boiler until I
returned. This was made from a piece of plastic tubing which had housed a
large, spring-loaded party popper which just happened to be the right
diameter. The depth of the boiler had to be considerably reduced to
allow the battery to fit between the side tanks (see below).
The mouldings provided by GRS for the safety valves seemed to be missing a couple of vital components - the coiled spring and a the actuating lever. The spring was fashioned from a coil of multi-core solder ......
... while the lever was cut from a sheet of brass. The whole assembly was fixed atop the firebox and filler applied and smoothed to fill the inevitable gaps.
Before moving to the next stage, the battery was fitted into the body. Because the motor housing is quite prominent on the chassis, there was very little space in which to fit the battery pack. I opted for a 12v 6800mAh Lithium-ion battery which can be obtained from China via a well-known online auction site.
The pack was too long to fit into the available space and so the outer casing was removed, as was the integral switch and wiring loom.
The battery pack could then be slipped in towards the front of the side tanks. At the same time a quantity of .22 calibre air rifle slugs were poured into the back of the smokebox and fixed in place with liberal amounts of Superglue - I know from experience that my locos benefit from as much additional weight as I can squeeze in.
The battery was then shrouded in masking tape and the body given a couple of coats of grey Halfords primer from a rattle-can aerosol.
The interior of the cab was then painted in acrylics.
..... and ½" fibre washers were glued into the spectacle openings.
The rear of the cab was also primed and fitted-out with washers, before being re-glued on to the body.
Pieces of lead, cut from a length of roof flashing were glued into the bunker to provide some additional weight.
Once the lead weights were firmly fixed in place, the rear of the bunker was
cut out from 1mm thick (40thou) plasticard and glued into place.
The trailing bogie was tackled next. Firstly,a new pivot bracket was attached to the rear of the chassis block and drilled to accept the pivot. As the chassis splits down its middle, this plate was glued only to one half of the chassis with Superglue which seems to be the only adhesive which LGB plastic will accept.
A corresponding hole was drilled in the end of the pivot arm for the trailing bogie ..........
.... and a 2mm bolt was passed through and held in place with a double lock-nut to allow the pivot to swivel without becoming unscrewed.
A cradle for the axle boxes (from GRS) was constructed from 2mm plasticard .......
After testing and finding the bogie had a tendency to derail, a support
for the pivot spring-plate rescued from the original U-class model was then attached above the pivot. The pivot arm was also shortened to bring the trailing bogie closer to the main chassis. This was another compromise - the trailing bogie should be further forward but I was concerned that bringing any closer to the main chassis would lead to problems over some of the tight curves and the LGB R1 points which I have on my railway.
The chassis was washed and scrubbed thoroughly to remove any signs of grease and then the upper section was masked before being given a couple of coats of grey primer followed by a couple of coats of satin black.
At this stage, I decided to install the rest of the electrics. I was using a Mac Five motor controller from Brian Jones and a transmitter / receiver set which I had acquired cheaply from the ubiquitous online auction site ..............
The wiring circuit for this set-up is fairly straightforward.
The fuse or auto circuit breaker (obtainable from Brian Jones or from Maplin - Order Code: AK08J) is quite important, given the propensity Lithium-ion batteries have for catching fire if short-circuited it's a wise precaution. The 2.5mm DC charge-socket (Maplin order code - JK10L) was wired-up first, followed by the switch (Maplin order code FH36P), with heat-shrink insulation (Maplin order code - N03FT) covering all the connections as once the wiring is stowed away it will be fairly inaccessible.
Then all the components were packed into the various nooks and crannies which had been left for them and the remaining space in the side tanks was filled with chunks of lead hacked off the weights in the original loco.
After some initial test running, I tackled the cab handrails. The upper supports were fashioned from 1mm thick brass sheet and the handrails themselves from 1.5OD mm brass tubing.
The handrail assemblies were then glued to the tops of the cab sides with the bottoms of the handrails slotted into appropriate holes in the footplate.
And a little more test-running was then called-for.
To fill the void underneath the cab, two sideframe sections were fashioned from 2mm thick plasticard.
These were then attached beneath the cab .......
.... and a piece of lead weight from the original U-Class loco was glued between them......
..... while another piece was cut and inserted into the chassis between the cylinders to counterbalance the weights fore and aft.
Two lengths of 1.5mm OD brass tube were shaped and inserted into the ends from cheap retractable ballpoint pens and glued beneath the sandboxes. The buffer beams were also cut out and rivets applied (from Cambrian Models - Order code NA7).
After adding some cosmetic filling and rubbing-down with fine emery, the interior of the cab was masked off ........
...... before a coat of Halford's Rover Brookland's Green was applied from a rattle-can aerosol. Once this coat had hardened off, it was rubbed-down before another final coat was applied. The buffer beams were then picked out in red Plasticote paint and the subframes were painted with black acrylics. The top rim of the chimney and the spectacle frames were painted with Plasticote brass paint. Crushed coal was glued into the coal bunker with exterior PVA.
And some more test-running was carried out until the battery became exhausted.
I hit a small problem when recharging the battery until I realised that the 1.6 amp auto-reset fuse was preventing me from recharging the battery at 2 amps (obvious really) and so the charger was reset to charge at 1.2 amps.
I now turned my attention to the smokebox. First of all it was painted matt black - black acrylic to which some talcum powder had been added. I then drilled three 1.5mm holes to take the handrail knobs - cast in whitemetal and available from GRS.
A handrail knob was threaded on to a 60mm length of 1.5mm OD brass tube which was then shaped to fit the top of the smokebox.
The handrail was then fitted to the top of the smokebox with epoxy. At the same time, the smokebox door handle (rescued from the U-class loco) was glued on to the smokebox door.
Holes were drilled into the top of the side tanks and the front of the cab, to take the handrail knob and handrail. The handrail was then attached with Superglue.
Four guides and two angles were fashioned from 1mm dia brass rod. The angles were soldered to the end of a 100mm length of 1mm rod and the guides were fixed into holes drilled near the rear edge of the side tanks.
The long rod was then threaded through and on into the front of the cab. The angle was slotted into the back of the sandbox and everything was fixed in place with Superglue.
The nameplates were then glued on to the sides of the tanks with epoxy.
The loco was then test-run again.
After putting the loco into service, I became disappointed in her performance. She seemed to struggle up some slopes and run away down others. At first I assumed this was a feature of battery control which, unlike DCC control, does not include load compensation for the motor. However, after some enquiries on the G Scale Central forum and some close scrutiny of the loco under load, I realised the problem was being caused by the bracket supporting the valve gear rubbing on the track.
I realised that on the original U-class loco, the upper end of the bracket hooked into a part of the footplate which I had removed. I decided that I needed to replicate this missing piece of superstructure. Casting around my various odds and ends, I happened upon a length of 6mm wide and 1.5mm thick brass strip. This was bent to fit over the motor block.
I then filed a slot into each end to accommodate the upper end of the valve gear bracket and then a short piece of 0.5mm diameter brass rod was soldered to the end of the new bracket.
The top of the valve gear bracket was then slotted into new bracket and the brass rod bent round it.
Two holes were drilled into the upper part of the bracket and a couple of self tapper screws inserted to hold it in place.
Since writing the above, the loco has been fitted with a driver made from Fimo and a brake standard in the cab.
I am still in two minds as to whether to line the loco in gold as all with other locos in the fleet. Somehow, leaving her in an unlined state gives her an even closer relationship with Wenhaston, the Southwold loco on which my model is based.
My researches have shown that although Wenhaston was lined when delivered from Manning Wardles, she was then painted plain dark green, which she retained until she was scrapped - though in her latter years her paint faded and her underlying original livery began to show through:
Wenhaston towards the end of her working life - Source: Southwold Railway Trust
There are still a few more detailing jobs which I would like to carry out - adding the brackets and fire irons on the back of the cab as in the photo above and re-shaping the valve chests to make them more closely resemble Wenhaston's.
In the meantime, a sound card has been added which includes a coasting effect varying the volume and tone dependent on whether the loco is accelerating or decelerating - see How I added a steam sound card to a battery loco
Update -27/5/17
Following a request for dimensions, I've taken some photos of the finished model alongside a ruler. Hopefully, this should provide sufficient info for anyone wanting to follow in my footsteps. BTW - the loco is 90mm wide and 272mm long (buffer beam to buffer beam). I've realised that the ruler can be misleading as it is closer to the camera than the model in some of the photos.
