In January 2001, the chance viewing of a TV news item about a Model T Ford on rails prompted some phone calls to determine its where-abouts and operating times. A slight detour on our way south for our Christmas holiday enabled photographs and basic measurements to be taken of this cute replica.
It is made to a scale of 1:24, to suit the NZR gauge of 3?-6?.
The wheels were made as follows: I cut out two brass disks each 2.5mm thick to the rough diameter of the rim and flange. This was done by hacksaw and disk sander, rotating the blanks about a nail through a 1/8th inch hole. These two disks were then soft soldered together and onto a piece of hex brass with a 1/8th inch hole and a length of brazing rod down its centre. The hex brass stub was held in my Unimat 3 chuck. A lot of very careful turning/measuring produced my first wheel. After drilling a centre hole for the axle, and having removed it from the chuck, careful application of heat separated the new wheel from the stub! The other three got easier as they were done.
Brass wheel bits. Two roughed rounds, hexagonal chucking piece and finished wheel.
To achieve the necessary electrical insulation between the wheels, I turned plastic bushes/sleeves to go inside one wheel centre on each axle. The body generally was made from brass sheet and brass rod. I found these easy to work with and to soft solder together. The window framing is from suitable sized wood strips. The roof is cut out of polystyrene, filed/sanded and covered with fabric using PVA glue. The radiator is wood, with fine brass mesh for the core. The bonnet vents are simulated by lengths of copper wire passing through holes at the top and bottom, with filler fillets along their front edges. The wheel ?tires?, hubcaps, door handles and radiator cap were chrome plated.
Early stage, no mudguards or steps yet.
Motive power is provided by a cheap 3-4.5v electric motor connected to the rear axle via a worm gear and pinion reduction of 15 to 1. The gears came out of an old electric eggbeater, with some re-bushing etc.
I chose to make it battery powered. This also allows it to be independently and automatically controlled in a forward/reverse cycle.
To do this a reed switch is mounted under the back axle and operated by magnets on the track to initiate the changes of direction. A 9volt battery powers a control circuit triggered by the reed switch. The model stops for 12 seconds, then starts again in the reverse direction. There is another delay (4 secs) incorporated to ignore the magnet most recently passed over. Two miniature relays switch the 3-volt (2 x AA batteries), supply to the motor. When initially switched on, there is a 12 second delay before starting forwards.
2 x AA batteries, 1 x 9v battery, and Vero circuit board.
Worm and pinion gears, read switch in rubber sleeve, ON/OFF switch and one of the relays.
Magnet under front axle. (see future thread for its purpose)
My model on the steps of the prototype, and an N or Z? scale model on top of mine.
Schematic diagram of control board.
The model has a scale speed of about 50kph, and it runs for hours on one set of batteries. The model was very suited to my ?there and back? garden railway line, with one magnet situated at each end of the track.
The main problem was that the real thing did not travel long distances in reverse like mine did.
