Improving the Trix PBA coaches (1)

Page created on 02/07/2024; updated on 09/07/2024.

Märklin-Trix TEE PBA A⁸tu.

I’d been looking for a long time to complete my seven-car train set acquired in 2008, part numbers 23408 and 234089: I was missing a generator van and a kitchen coach to make a complete Paris - Amsterdam composition. Now there’s a reference 23493 released in 2017 that includes precisely these coaches: I recently found it at Modellbahn Ritzer on ebay.

Note that between these two series, there are a few inconspicuous changes.

• the first generation was delivered with two types of buffers and bellows, compressed or not. This is no longer the case: the coaches are fitted with compressed bellows and… uncompressed buffers. This is why the A⁵rtu buffers are deformed by the packaging, which was designed for shorter buffers!
• The ballast has been reduced, which is a good thing, but it’s still too heavy. Have a look at this photo. From front to back, the 1st generation ballast, the 2nd generation ballast, and finally the one I finally installed.

Remarks:

• the lighting strip support crosspieces are already installed on the interior fittings. I’ll come back to this later;
• dismantling is very easy: remove the UIC bellows and pull on the chassis while gently spreading the sides of the body.

I take advantage of this recent purchase to explain how I modified these coaches, just like the Hornby-Jouef Mistral:

• lighting;
• end of train lights;
• function decoder.

How the coaches are powered

A function decoder is installed in each A²Dx generator van, like in the A⁴Dtux Mistral. The coaches are powered from the vans by conductive couplings. Like the vans, one end coach is fitted with tail lights and a Fleischmann Profi coupling head.

This arrangement made it possible to mix the PBA and Mistral coaches, as in reality, and also to have train sets with two sections: one Paris - Brussels and one Paris - Amsterdam, with, depending on the period, two A²Dx vans or one A²Dx and a mixed A⁴Dtux coach.

Miscellaneous modifications

These coaches are a little too low, which is noticeable and annoying when they are mixed with Mistral (HJ or LS Models). Here’s an example with a Mistral LSM (left).

They don’t have three-point suspension. Generally speaking, their design is a little rustic, with very few add-ons, particularly on the Y24 bogies — the REE bogies are much more detailed. The wheels are Märklin standard (NEM 340), i.e. 3 mm wide instead of 2.8 mm, with 1.2 mm flanges and a back-to-back distance of 14.2 mm compared with 14.5 ± 0.1 for the NEM 310.

Similarly, the one-piece interior, with only a touch of paint on the seats, is rather crude, and the basic colour, a very dark red or grey, doesn’t correspond at all to the general shade of the real coaches.

All this will be subject to modifications.

Three-point suspension

The two-point seat at the other end can be made with spacers of various shapes. I’ve found it practical to use pieces of Evergreen ⌀ 3.2 tube with a 0.3 mm milled flat on them to adjust their height, and also make it easier to glue them in place.

Here are the spacers.

Naturally, these spacers will be painted grey.

I have to point out a disadvantage of raising the bodies: the steps, fixed to the bogies, are too far away from the underbody. That said, the manufacturer didn’t bother, fixing all the steps in the same place, even though in reality not all the access doors are at the same distance from the ends of the coaches, as shown in this extract from a diagram of an A⁸tu — see dimensions highlighted in green!

Finally, raising the height implies the need to increase the pivot clearance in the chassis. This means dismantling the interior fittings, which is easy, taking care not to lose the drawbar return springs, as the brass plates that hold them in place can easily slip out. These plates have had their tongues removed, and their wings spread (from 26 to 27 mm) to improve their fit under the chassis lugs.

On the left, untouched part; on the right, detached tongue.

The bogie pivots are milled using a 7 mm drill to a depth of around 0.8 mm.

The drawbar is temporarily held in place with adhesive tape.

Result of the raising:

Remarks:

• The bellows are joined using my conductive couplings; with Märklin or Profi heads, there is a gap of at least 1 mm between the coaches.
• It’s normal for the TEE strips to remain offset, and this is one of the characteristic differences, along with the bogies, between the PBAs and the so-called Mistral 69.

Photo by G. Renai in Le Train, Archives de la DEV, volume 2, page 31.

Replacing the wheels

The best solution is to replace the wheels with ones that conform more closely to NEM 310, bearing in mind that the distance between axle tips is 24.4 mm. You can also machine the original wheels; I’ve done this for some coaches. We’ll see an example of this in the section Electrification of A²Dx generator vans.

Dampers on the generator van

On the bogie on the generator side, additional dampers have been fitted, not shown by Märklin-Trix. However, the attachments are present.

These dampers are made from Evergreen ⌀ 0.8 × 4.5 mm rod, slightly rounded at the ends, and thinned with a file by about 1/10 mm over half the height. They are glued with CA glue, then painted in Humbrol dark grey No. 32. Unfortunately, the original central damper looks much smaller than the new ones…

We also notice that the brake blocks are not in front of the wheels…

Improving the decoration

As already mentioned, the dark red colour of the interior doesn’t correspond at all to that of the real coaches, whose decoration is rather light. As I mainly have B & W photos, I had to make do with ivory paper stuck on with thin double-sided adhesive tape.

Here’s an example of the A⁵rtu kitchen coach, whose tables were painted in Humbrol acrylic white. There were probably no tablecloths, as these tables were retractable into a box under the windows.

All this remains very basic. In particular, the doors leading into the room are not shown. However, this is hardly visible from the outside. This photo also shows the power supply wires for the lighting, which we’ll come back to later.