I am wondering if any one has knowledge of how to adjust the steam locomotive chuff rate in Lionel’s TMCC system. Or, put another way, what would make the chuff rate on a two cylinder locomotive sound like it had 3 cylinders? (The loco is a 2-10-4, some of which may have had 3 cylinders on the prototype.) I can’t find anything in the TMCC books on adjusting the rate. Any help would be greatly appreciated.
Sodbuster
Most of the loco’s do not have adjustable chuff rates. The rate is fixed by a mechnical cam (usually tied to the smoke unit) or by means of a magnetic sensor on one of the wheels. The majority of engines are set up for two chuffs per revolution (this is usually wrong but its sounds better at higher speed). Some TMCC/RailSounds retrofit kits use a VCO to adjust the chuff rate. This is an electronic circuit that generates pulses to stimulate the Railsounds board to generate chuffs and can be adjusted to whatever rate you want by adjusting a small potentiometer on the board. The only way for a mechanical unit to malfunction is for the cam to have lost a lobe or one of the magnets to have fallen off of the wheel/axle. If the engine is one of the few that has an adjustable chuff rate by way of the TMCC system, the programming procedures will be in the owners manual.
If room permits there is the possibility of adding a second reed switch ( or cherry switch ) on the opposite side of the mechanical cam Chuck refers to in his first example. You’d still only have 4 chuffs per revolution and I assume a 3 cylinder loco would produce 6 chuffs per. The aggrevation and finicky engineering problaby isn’t worth the effort but it is an option. Just a thought.
On the same type of reed switch I was able to produce 4 chuffs per revolution by removing it’s return spring and attaching fridge magnet material to the switch lever. This type set up cycles the switch twice as often per cam cycle. So, one switch such as this and another properly working reed switch on the opposite side of the cam could produce 6 chuffs per revolution timed so that each chuff could be heard individually. Complicated to say the least!
Bruce Webster
TMCC as far as Lionel has a set chuff rate as mentioned by using cherry switches to achieve usually 2 or 4 chuffs. I’m guessing the engine in question with 3 cylinders should prototypically have 6.
There is a way to achieve six. It will require buying a drop in EOB board and adding a timing tape to the flywheel as well as soldering a wire to the reciever. In setting up EOB on a steamer you go through a series of programming using Cab 1. You are basically trying to set the chuff at one per revolution. EOB counts the stripes on the flywheel to achieve this. After that is done you simply select the chuff from 1,2 or 4 with a few button pushes. In your case you may have to set the engine up with 3. Then simply dial up 2 on your Cab 1 and you should have 6.
Your can get info as wel as manuals from www.tastudios.com They will even do the install for you and will help you out over the phone if you have any questions.