Now what impressed me the most was that when I went to remove ancient fluff from its worm, I discovered that it wasn't a worm, but instead a spring that looked like a pen spring was used as a worm! I have never come across this before!
It has a very long motor shaft with a spring on it, which turns a massive cog which in turns drives two little cogs, one on each axle which drives all four of the wheels. (There are no con-rods. Only piston rods).
There is a counterbalance weight at the front as the motor in on the back, and a loop of card to cushion and hold the chassis into the body. The reat is clipped into position via a pair of square tabs which the body squeezes round rather like 1980's Lima and Hornby models used to clip their bodies onto, but these tabs are square and are not noticable unless one knows the are there. (The front of the chassis simply slots in place by pushing the chassis forwards into the body).
Now the loco is made with children in mind as in those days most things were, but credit where it is due. Consenting style card to cushion the chassis and a spring as a worm to enable the drive to have a little "Give" if it is forced. It is probably why it is still alive all these years on! (I have not tried the loco as it needs a good clean). I thought I would share how it is made as it is interesting!