during last months I have been working on a new project: the BR 84-009

This new steam locomotive (8 studs wide) has a new original pistons movement and as my previous BR 94-1292 has a single long frame of 10 wheels.

This locomotive under the hood has a 9 volt battery to light up the two front lights and red rear lights; the switch is in the back masked by coal.






The real challenge with this new BR was to create a propulsion system powered by my usual cabose locomotive that would allow a synchronized speed between both of them (BR and caboose).

I have to thank once again Teddy
Before continuing I’d like to share a little bit of theory:
You can find the rpm of each lego motor here: lego 9v compared characteristics than you have to know the perimeter of the wheels (ex: 9v train motor rpm x diameter x PI 3,14) so you can find the distance covered by your train in one minute.
Theoretically a standard train motor 9v (only the motor with four classic wheels and no other weight) cover 110 meter in one minute: 2000(rpm)x 1,76(cm. wheel diameter)x3,14(PI)=110,52m.
Now if you want to cover the same distance with a PF medium motor with the new lego large train wheels you have to regearing, because this combinantion cover 38 meter in one minute: 405(rpm of medium pf motor)x 3,00 (cm. large wheel diameter)x3,14(PI)=38,15m.
You can use, for example, a 24 tooth gear as pinion and a 8 tooth gear as crown wheel: 405(rpm of medium pf motor)x 3,00 (cm. large wheel diameter)x3,14(PI)x24(tooth gear)/8(tooth gear)=114,45m.
My original idea to avoid any difference in speed (after regearing) between the two locomotives is a clutch system.



To respect the original aspect ratio hiding battery, motor and clutch gear I’ve used a useful SNOT technique.





Thanks in advance to Toastie
Enjoy the show!






Merry Christmas to all
Edited by LEGO Train 12 Volts, 29 December 2011 - 07:58 PM.






















