The original idea behind this project comes from Mr. W.B.Hamilton, who wrote an article for the British HO Society. The article is available on-line here, in Adobe PDF format. This project expands and integrates the original article, adding all the missing informations required to have a finished model. It also adds a few more functionalities to the model.

The starting point is the classic, vintage Lima HO 4 wheels tank wagon. I obtained a few of them through eBay, but they are quite common at swap meets and exhibitions, not necessarily in the UK. They come in a variety of liveries and registration numbers, from slightly inaccurate to utterly fake. Some of them have British tension-lock couplers, but also common are models with continental loop ones. Hornby also seems to have reissued the same tank wagon, in the Lima range, with a minimum of retooling. A few of these new items already appeared on eBay, as continental wagons.

For this project, we want to build a rake of three wagons. They are all TTAs, with some little detail differences. The first part is common to all three, the differences are explained in the second part.

What you need

Entering the workshop

The first step is very simple: dismantle everything that is not glued!

Remove the couplings by simply pulling at them. Remove also the wheel sets. The platform handrail is a metal part. To remove it, locate the two twisted tabs inside the buffer housings and, using a  needle pliers, twist them back into alignment with the plastic slots. The handrail should slide off effortlessly. All these parts need not to be reused, so do not be overly cautious trying not to damage them---the important parts are the tank, the frame and the buffers.

Carefully remove the ladders and the walkway around the filler cap. The walkway is kept in place by the cap itself, which in turn is often glued to the tank. In this case, there is no other way but to break it off. The ladders are attached to the solebars with two pegs. On my three samples, in one case they were simply plugged, on another one they were glued and in the third one they were melted in place with a soldering iron. I expect you will possibly find other variants. In any case, try to remove the ladders whole and undamaged, as they must be almost completely reused.

Update 27th August 2007: I got today via eBay another tank wagon. It seems to be a fourth variation, from a newer mould, with a platform plastic handrail instead of the metal one, a different style of ladders solebar plugs (bayonet-like, arrow shaped) and a different underframe, much less detailed than before and with a very clumsy, boxy structure in the middle, from axle to axle, which houses the weight. Amusingly, it is painted in a quite nice Amoco "Bromford" livery, looking very british with even a printed "No naked lights" warning on the sides. It is marked TEA AMOCO85600, but a TEA is a bogie wagon.

It looks like Lima managed to retool a model and actually worsen it. It is less easy to convert than the older type, so avoid it if you can.

Cutting

Using a razor saw, carefully cut away the bufferbeams and remove some 5mm of underframe on both sides. As some major structural parts are going to be cut, run a drop of polystyrene glue inside the solebars, where the tank touches them. This guarantees that the solebars will not spread apart.

Using the same razor saw, a pair of cutters and the shaving blade, remove all frame details under the axles, between the bufferbeam and the inner frame trusses. In this pictures you see the bufferbeam already in place. Well, it was my mistake, leave it off until the cutting is over.

When this messy work is finished, slightly sand the back of the bufferbeams and the solebars heads. Both should be as flat as possible. Glue the bufferbeams back in place with polystyrene glue and check that the frame is square and true.

Once satisfied, let dry thoroughly. Once dry, take the chisel blade and carefully remove the data panel moulded on the lower right of the tank. Please be careful and mind both the tank and your fingers. Both should come out with no damage. Smooth out any tank imperfection with putty and wet sanding, but try not to destroy the rivet details between the tank and the solebars.

At the end you should see something like the picture on the left.

As final touch, sand the buffer heads to flatten them a bit and to reduce their unrealistic thickness.

Now, with 0.4mm plasticard, prepare two rectangles and four "T" shapes. Use the templates available here, or click on the templates thumbnail. The drawings are in PDF format.

Glue each rectangle against the bufferbeams and the solebars, taking care that they must be flush with the underframe topside (the underframe has to be flat when seen from above). Once dried, stack the "T" shapes over the rectangles, the "T" leg pointing between the wheels. Again, they must be flush with the bufferbeams. These parts will be the foundations for the close coupling cams, so precision and planarity here is a must. Note that the overall thickness of this sandwich must be 1.2mm (i.e. 3 x 0.4mm).

Now, using a fresh shaving blade, slice off the eight brake shoes and set them apart.

Attach the close coupling cams in place with AC-glue. Abutting them against the bufferbeam will leave about 1mm between buffers, when  the wagon is coupled. Pull the cams 0.5mm backwards if you really want to achieve buffer contact. The best thing you can do is to insert a suitable thickness of polystyrene, this ensures the desired spacing and reinforces the joint.

As you have already some cutting tool at hand, cut two V-shaped notches under the axleboxes, deep enough to ease the fitting of the axles but still shallow enough to keep them in place. This helps avoiding unnecessary spreading of the axleboxes during the next steps, when there will be a lot of glued things you don't want to come off.

Now, using a 2mm x 1.5mm plasticard strut, make eight small stubs and glue them behind the suspension hangers. Put a wheelset in place for reference and glue the brake shoes back into position, this time in-line with the wheel threads.

You should get something like the picture below (minus the axle, of course).

A word about the close coupling cams. Roco makes two types: a slim one and a fat one. The above picture shows the slim type, which fits like a glove in the narrow quarters of the TTA frame. If you use the fat type, you need a few adaptations. First, snip away the two protruding wings. Second, eat away some of the plastic from the slanted frame sections, as it would foul the wheel rims once in place. The coupler on the platform side has some more room, the opposite one is a bit more critical. Proceed with care and dry-fit until satisfied.

The picture here below shows the original part (right) and the slimmed part (left).

The superstructure and the different details

The structural part of the underframe is completed, now what remains is to decide the design code, which, in the BR parlance, is the actual set of constructions details used for a specific piece of rolling stock.

In these particular models, the design code translates into which combination of ladders styles, walkways shapes and underframe equipment you prefer. The nice thing about TTA petroleum tank wagons is that there seems to be an almost infinite variety of design codes, each one with subtle differences.

From now on, you are free to pick up you preferred design code. What you really need is a good picture, and the books in the References Section have plenty of them. I picked up three different ones but I do not claim to have strictly followed any of them, I just reproduced some of the most obvious features.

In the picture below, you can see the three different types I built.

The above mentioned photo shows the tanks still without much details, like braces, struts, tank piping and, most important, underframe brake gear. It shows, though, the main difference among the selected design codes.

The yellow one has an intermediate length walkway, bent ladders reaching the solebars with separate lower steps and a separate smaller platform not reaching the tank top. It is based on Design Code TT026X, with the only inaccuracy of double link suspensions instead of single link ones. With an additional auxiliary brake lever it could also be a TT088K, and in this case the double link suspensions are correct.

The white one has a short length walkway, bent ladders mounted outside the solebars with a deeper first step, almost in line with the roller bearings, and the same separated top platform of the previous example. It follows the TT088P design code but it could also be a TT096A.

The last one, green, has full-length walkways, flush top platform with gently warped ladders mounted on solebars tops and separate simple additional step below the solebars. It follows very closely the pattern of a TT027T. This model has also the so-called petroleum "Hazchem" panels separately mounted on the solebars instead of it being affixed to the tank. From the model point of view, it is important that the size of this panel matches to the size of the decal that will be placed on it. If you use the Fox Transfers solution, as I did (see further on), then the panel is a 9.5mm x 5.1mm rectangle.

In all three models, the walkways are made of 0.3mm plasticard foil, cut to shape according to the templates provided here for TT026X, TT088P and TT027T (all templates are PDF files), glued in place and finished with small fixing struts made of stretched sprue and plasticard thin strips. All other details are either stretched sprue, plasticard rods of various diameters or 0.2mm plasticard foil.

TT026X

TT088P

TT027T

In all of the above photos you see the underframe details and the handbrake arrangements, along with other details, like the side panels of TT027T. The TTA underframe is especially tricky.

I have pictures showing the wagon sides. From these pictures, the single discharge pipe below the solebars between the wheels, plus some sort of boxes hanging flush with the solebars is clearly visible. Also very clearly on display is the handbrake lever arrangement. These features are reproduced rather faithfully.

The remaining underframe equipment is visible only in some design codes, and it is obviously showing a cylinder of some kind (centre offset, closer to one axle) and some piping. For this detailing, I simply had to guess and not wanting an empty underframe, I recycled some parts I had in my spares box (not necessarily train parts), trying to convey the look and feel of a brake pipework. Two of the discharge pipes are unused parts coming from the HTP tank wagon project and the same applies to the brake cylinders. The remaining white parts are just bits of polystyrene, mainly small rods and 0.25mm foil. Only the handbrake lever, in order to be believable, requires a bit of shaping according to the small drawing provided here (as always in PDF format).

Entering the paint shop

As I wanted to underscore the subtle differences between the different design codes, I elected to paint the three wagons in the same livery. The choice fell on the modern BP style, basically because I have a lot of pictures of it. It also offers the option to model wagons with the company logo and the more recent variant without it.

The livery is very simple: overall green above the solebars and roller bearings caps, yellow solebars, underframe and buffers black and details picked up in white. The white details vary with design code.

Before painting, each model is stripped down of its wheel sets and couplings, washed in lukewarm soapy water to remove any trace of grease and fingerprints and let dry thoroughly. The close coupling cams are then wrapped in masking tape, taking care to protect the moving surfaces. The model is then coated with a layer of Railmatch 506 enamel primer white.

The next step is painting the solebars. I used the Tamiya XF-7 acrylic, which is a nice match for the original BP yellow. Do not worry unduly if the yellow goes also around the solebars, as it is the lightest colour of all and will be easily covered by the next layers.

Mask the solebars. The underframe is next in line and gets painted plain black. This time I used the Tamiya X-1 acrylic.

When the underframe is dry, mask it and paint anything else green. A suitable shade of green is the Italeri/Testors Model Master 1571E flat green enamel.

Once dry, pull all masking tape and behold the final result. If nothing went wrong, you should obtain something like this:

Of course, now there are still some final details to be added, like black buffers, green roller bearings caps, white handbrake handles and a general paint job touch-up. It is also time to apply the decals.

The decals I used are Fox Transfers for 4mm/OO scale. The size difference is almost unnoticeable. I used F 4120 and F 4126. The BP logos are F4124. The "Hazchem" panel (i.e. the orange rectangular one with the black flame in the lozenge-shaped orange patch) carries the code 3YE which, if I am not mistaken, is for fuel. The TT027T prototype I modelled carries Gas Oil (whatever it is) and it should carry the code 3Z. I decided it is an imperfection I can surely live with.

I will not describe where each decal goes. The best you can do is get a picture of the particular wagon you want to model and copy it.

The final result

Here you can see how the finished rake looks like, being shunted by a Class 08 engine (the shunter itself is a not yet finished, quite heavily modified Roco NS 5/600 of first generation, i.e. then-made with no NEM couplings, no flywheel, no DCC board, no anything) and coupled with Fleischmann Profi couplers.

I decided to dress the first TTA on the left with the BP logo of the '90s, while the others are in the more recent livery without logo. For the terminally curious, the actual pictures I used to model my TTAs are, f.l.t.r.:

• TT088P: BPO 37192 (Plate 56, p.32, Railways in Profile Series No.14)
  
• TT027T: BPO 53754 (Plate 74, p.42, Modern Railways in Profile Series No.3)
• TT026X: BPO 37267 (Plate 82, p.46, Modern Railways in Profile Series No.3)

The decal set I used is not entirely accurate, as for instance it has the mandatory "No naked lights" plate only in black typeface. Not wanting to order another decal set and having seen a number of field variation in other photos, I decided to put the black warning into a white rectangle. A word of wisdom: the white decal patch comes from a Microscale sheet. Maybe I own a defective one, but my experience with was a real pain. The Microscale decal does not stick at all, be the surface finish gloss or flat, and it reacts badly to the same company Micro Set and Micro Sol, turning a nice yellow shade  after drying up. I will surely replace it soon with a Fox Transfer equivalent.

The wagons are missing the running numbers, as, although it is a quick and easy job, I still have to order the corresponding decal sheet.

The wagons are still in pristine conditions, hardly an accurate depiction of BP tankers, especially for the "logo" one. Ironically, the actual picture of BPO 37192 shows it just out of the workshop, without even some brake dust! Eventually, all three tankers will receive some very subtle shadow highlighting, and the same applies to the 08, too. This is mainly needed to highlight the underframe details and the tank rivets, and to give some depth to the solebars.

Here you can see some additional photos of the single tanks, again f.l.t.r. TT088P, TT027T and TT026X:

and here I tried to take a rake picture from a 1:87 human point of view.

I think it looks convincingly real. I am very much tempted to add more details and replace some parts, like fitting bufferbeam pipes, Finescale wheels and using photoetched walkways and ladders and new, more realistic sprung buffers. On the other side, though, I am quite happy with the current result.

I especially like the unobtrusive appearance of the Fleischmann coupler, small and compact and yet allowing the rigid connection needed by the close coupler cams. Its only drawback is the proportionally high force required to couple the wagons, but I suspect it will decrease with the use.

Well, I think the final TTAs look good enough for being some old cheap Lima chunk of plastic, do they not? They run on scale wheels, on scale tracks, they are close-coupled, things that even today are not that granted for the ready-to-run OO market. I hope this project interested you enough to get a look at the British HO Society activities and, why not, join it.

References

1. British Railway Air Braked Stock Volume 3 (Modern Railways in Profile Series No.3)
• by Tom Smith,
• Paperback 64 Pages
• ISBN-10: 1900298317
• ISBN-13: 9781900298315
• Publisher: Cheona Publications
• Pub date: 2004
• Source: Transport Diversions Emporium
2. British Railway Private Owner Tank Wagons (Railways in Profile Series No.14)
1. By R.Tourret
2. Paperback 64 Pages
3. ISBN-10: 1900298171
4. ISBN-13: 9781900298179
5. Publisher: Cheona Publications
6. Pub date: 2001
7. Source: Transport Diversions Emporium