The regulator is the main stop valve of the locomotive. It will control the passage of the steam to the cylinders, so that you can control the speed of the engine at any time. A standard Stroudley type disk regulator was drawn for this loco. I find them reliable and relatively easy to make and the large dome is very suitable for this type of regulator. The range of rotation between closed and fully open is 60 degrees, which allow a gradual opening and hence good control over the driving speed. Although this is a German locomotive, the regulator is closed, moving the regulator handle to the right and opened by moving it to the left (like most of the English locos) This was typical for the Württembergische Staatsbahnen.
The main body was milled from a 20 thick bar. Straight forward milling job with a large end mill.
In this set-up you see the drilling of the small hole, taking up the end of the regulator rod. To get it exactly in line with the hole for the main steam pipe, a short piece of threaded rod was positioned in the vice and set to zero on the digtal read out. The body was screwed on top of it and the hole was made.
The main body with a 4 mm thick bronze disk silver soldered to it. Two holes of 5.5 mm are used for taking of the steam from the boiler when the regulator is fully opened.
Stainless steel operating links of 3 mm thickness and 8 mm width. M4 stainless steel bolds were made to keep it in place.
It just fits in the dome.
The main steam pipe is 12 mm round bronze, but has a 7 square hole. This was filed by hand, for taking up a piece of square steel.
This piece of steel can be used as a wrench to screw in the steam pipe in to the regulator body. This was designed this way, so that removing in the future for maintenance should be possible. Alan Beard from Bedford ME told me that he had trouble removing the steam pipe from his 7¼ Marie Estelle 0-4-0 loco after 25 years of service. This was the more often used copper pipe arrangement (the same with my 3½" and 5" locos), which only has a small slot at the end of the pipe. A large screw driver should do the trick of removing it, but over the years it will be chalked up a bit, and more force will be needed.
The set up in the boiler. A small piece of wire, bend in a hook, is used to catch regulator rod to position it for the square hole
The bottom part of the linkage; a piece of 1 mm stainless steel wire will secure the bold from working loose in service; which really would present a problem: How to retrieve the small bolds from the boiler.
A cloth is used to close the boiler; so no parts are accidently dropped in the boiler.
The last piece of wire in position. The V-shaped holes in the disk can be clearly seen: this way there is a gradual opening of the steam ports. A nice controlled and slow start of the locomotive should be possible.
The end stops of the regulator are on the boiler back head in the cab.
