Hi Don:
To answer your questions......Just about all of the fuel tanker wagons were made by Buco at one time or another. The company (Bucherer) went into liquidation in 1957/1958, and the fuel brands modeled were restricted to BP, Shell, and ESSO in short wheel base (2 axles) and the long wheelbase version with 2 axles per bogie. You will see some of these original tankers in the photos I have attached.
The original tooling and equipment from the 1950's, along with tons and tons of spare parts and unassembled wagons was purchased by some die-hard collectors in Switzerland and, over the ensuing years, (right up to present date) new models were released depicting more recent manufacturers (Aral, Gulf, Valvoline,Veedol/STP). See pictures.
I have successfully built several additional tankers myself using original spare parts still available from a Buco hobby store in Switzerland (Amiba Lokschuppen at Wetzikon), and these are the milk tanker wagons (white and blue in colour) and the Castrol tankers (green in colour). The chassis, wheels, buffers, couplings, along with the side identification boards, domes and ladders are all original Buco parts, but the tanker barrels are from ETS, a Czech Republic train manufacturer that are almost an identical fit. A quick glance and you cannot tell the difference.
In relation to the "little green boxes with buttons", they are the contacts for changing the position of the electronic track switches. One press on the red button that corresponds to the track switch, and the blades of the switch are moved to the opposite position. Most of the turn-out motors on my layout have a single solenoid system that works on the sudden input of 18V AC, but the button must be released quickly otherwise the solenoid wiring will get hot and burn-out. This was the first type of electric switch developed by Buco.
As time went by they perfected the switch motors to have a "double throw" action, and these switches are activated by a "toggle" type switch, which can also be seen in my photos. Toggle in the down position, the switch is thrown for straight ahead travel, toggle in the up position, the switch is thrown to allow the train to exit the main line. These switches are identified by a light bulb burning in the rotating lantern, where-as the older type switches only have a solid rotating wooden lantern. Please see the attached photos.
The third type of "little green box" on the console's are the ones that control the "Colour - Light" signals that are integrated with the 3 rail track, and actually stop an oncoming train if the signal is "red" using "interrupter" sections of track. Once the toggle is moved to the up position, and the light turns "green" the "cut" section of track is re-energised, and the train can continue under normal track voltage. A very simple way of controlling many loco's on the one main line in a realistic fashion using "cut sidings".
Sorry for the tutorial but it truly was an incredible "O" gauge 3 rail system for its time - 1947-1957/8. I hope you can follow my ramblings.
Peter on the fabulous Gold Coast in Sunny Queensland, Australia.
