The weather has changed a lot in March and April, so I started to work inside. The lettering of the wagon is done with the Silhouette cutter plotter and vinyl.
The inside of the brakeman's cabin painted grey.
The letters (font Alte Din 1451 Mittelschrift).
Fonts can be found on several websites:
https://www.1001fonts.com/alte-din-1451-mittelschrift-font.html
http://www.peter-wiegel.de/alteDin1451.html
As the Silhouette cutter plotter was setup, I also cut a logo for the wooden box (driver seat) for the open wagon. Living in Eindhoven (the Netherlands), a logo of Philips seemed nice, although there isn't much left of the company anymore in the city.
The letters can't be to small; the plotter than is not able to cut the vinyl correctly and the letters themselves are so small that they are hard to handle.
The dot on the 'i' for the text 'Station' is about 1 mm square. These have to be cut by hand; with the plotter these are so small that they can't be cut, without disappearing during the process. They will not stick to the backing paper any more, when the cutting blade is moving over them.
The letters of the brewery are not available as a font, and had to be drawn in Solidworks.
For this I've used a picture of the gauge 1 Märklin wagon, that was loaded as a sketch picture in the Solidworks drawing. Then every contour was traced.
A dxf file was created from the sketch; but Solidworks was a bit disappointing with this. Curves and some splines came out badly. So Siemens NX was used to convert the Solidworks drawing into nice dxf files.
This dxf file was imported in the Silhouette software and the letters arranged so that they will fit on the A4 format cutting mat of the plotter.
By moving the letters around, care has to be taken, not to change the size of the plot. 
Two sheets were cut; one for each colour.
Transferring the black shading to the red letters. Not difficult, but great accuracy is needed and it is very time consuming.
Removing the black shading...
....and sticking to the other sheet.
When all is done, the shaded letters are covered with transfer foil. It can then be pulled of the backing paper, ready for applying to the wagon.
The first letters; starting in the centre of the wagon.
The frame of the wagon only has 'simple' white letters. These small size makes the work cumbersome. When removing the transfer foil, the 'glue force' between the transfer foil and letters is sometimes greater than the 'glue force' between the letters and the frame. Thus when removing the transfer foil letters will still stick to that, and not to the frame. The dots had to be applied individual, due to this effect.
The frame fully lettered.
The lathe was used to paint the white wheel rim.
The steps still waiting for assembly.
To position the letters, a small indicator is applied. This helps to get the letter groups to be applied on the correct place.
This is almost the same way as it is done on this preserved wagon:
https://www.3seenbahn.de/Fotoalbum/rothaus-beschriftung/rothaus-beschriftung.html
The bigger the letters get, the easier it is to remove the transfer foil.
The 'indicators stripes' that were used to locate the letters.
The next group of letters, ready to be applied.
Once a group has been applied, they are firmly pressed down with a roller.
Cutting the black vinyl.
Removing the surplus of foil is the first thing to do, after the sheet has been cut.
The bigger the letters (58 mm high is this G) the longer the shadow is.
These have to be carefully removed; so that they stay in shape.
Removing the red section, only just prior before applying the black line. This keeps the backing paper as clean as possible. Otherwise dust or skin fat would get a chance to accumulate, and getting under the black foil. Sticking than to the wagon would be more difficult. Wearing gloves was not much of an option during this work.
Positioning the black shadow line takes more care, because the flexibility of vinyl makes it difficult to handle. They become also a bit static, so tweezers are sometimes also needed.
After pressing down on the wood, the thin vinyl foil (0.08 mm) even shows the wood grain.
Once the complete lettering is finished, a clear coat of varnish is needed to secure the letters.
Starting to look as the 'Wärmeschutzwagen'
A black mat vinyl was used for the destination boards, the white line area also cut with the plotter.
A ruler is used to keep the application (transfer) foil straight.
Shading the relatively small letters "Spezialität" was done by shifting the original letters in the Sillhouette software. It's a bit of a puzzle than to pick the right parts from the black sheet, to create the shadow.
Individual pieces are very small and difficult to handle. A pair of extra strong reading glasses was needed to see what I was doing.
With Coreldraw the letters can be arranged in a curve and still be the upright position. Solidworks doesn't has this functionality.
The photo of the original wagon at hand, for determine the correct position for these letters.
At the bottom of the wagon, the link to the Märklin model is made.
Waterslides (Decals) on the doors still have to be added.
The original wagon; only two were built in 1909. No. 600048 en 600049 by Maschinen Fabrik Esslingen as private owner wagon for the Württembergische Hohenzollernsche Brewer company English Garden Stuttgart.
The book
Geschichte der Eisenbahn-Bierwagen: Das erste Frachtgut deutscher Eisenbahnen: Bier.
ISBN: 3882554428 (ISBN-13: 9783882554427)
was a source of information for builing this miniature version of it.
Solidworks Rendering April 2021
Download of the drawing is possible via