The original with mine on its step.
started me on the track towards yet another model. The clip was of a Model T railcar which ran at Pleasant Point, south of Christchurch and inland from Timaru. I had already made a start on the Drewry railcar, however having made the bogies and basic chassis, I was stuck, not knowing what materials to use for the car bodies. Having temporarily put this model aside, the challenge of another much smaller railcar model was very tempting. As it so happened we were booked to go to Queenstown at Christmas, only weeks away🙂.
On a detour via Pleasant Point we found the railcar stopped at the old railway station. The line that formerly passed through the small township was now isolated and used to run the Pleasant Point Museum and Railway’s trains. It was not long before the Model T took off with a load of passengers. We pursued it by car and caught up with it stopped again at the Museum end of the line. Fortunately everyone on board had entered the museum for a look. Over the next wee while I took a selection of photos, including the most important four elevations, and measured as much of the car as I thought was necessary. We had left for Queenstown again, before anyone came back.
During our weeks holiday I drew the elevations onto paper at scale size (1 to 24). Having had the photo elevations printed out while away, I was able by scaling from them, to come up with reasonably detailed plans.
Two roughed rounds, hexagonal chucking piece and a finished wheel.
The first thing I tackled were the wheels, 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.
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 louvers are represented in the following way. Pairs of holes were drilled at the top and bottom of each louver. Thin wire ‘staples’ were fed through the holes their ends bent over on the inside. Filler was then applied around the edges of the wires. This was sanded, once set, to form an even fillet shape.
The wheel rims, hubcaps, door handles and radiator cap were chrome plated.
Worm gearing, motor and reed switch.
2 x AA batteries under the roof.
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 operated, (2 x AA batteries). This also allows it to be independently and automatically controlled in a forward/reverse cycle.
To this end, a reed switch is mounted under the back axle, 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.
The circuit diagram. A dual 555 timer is used. Having now been introduced to the PICAXE controllers, that could have been an easier option.
On the occasion of a subsequent visit to Pleasant Point Railway.
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.
This railcar has performed very well, travelling backwards and forwards on shuttle tracks at a number of Christchurch train shows (Pioneer Stadium). This may be why I have had to replace the motor once. Its very basic brushes had worn out!
This model has subsequently been modified slightly to work in with my turntable project.
A very temporary PICAXE set up.
As the model is, starting up and stopping are very abrupt, hardly scale like. I have played with using a PICAXE chip to achieve a ramping of speed control. However at this stage I have not pursued this very far because of all the issues it raises. I found that the model needed a short period of full voltage to overcome initial friction and get it moving. Also a ramped slowing down would be complicated by the need to have it stop on the turn table. Two magnets may be needed. One to initiate a slowing down, then another one to stop it dead in the correct place.
26.02 | 08:23
this is a beautiful model. I first saw a ststic DM model at Napiers Lillip...
29.04 | 04:09
Fantastic video Dean!
20.08 | 11:21
Thats great Dean love to see the video.