Convert RailSounds 1 Hall Sensor chuff switch to reed switch

Just use the wires from the hall switch. 

Rod Miller

Thanks for the suggestion. I have plenty of wire and would rather keep the hall sensor and it's leads intact should I want to put everything back.  Have you actually made the mod and did you run into any trouble. What I am concerned with, can the chuff circuit keep up with 4X the number of cycles.  and does it start to skip when the chuff rate exceeds some rate.  

I have upgraded numerous locomotives to 4-chuffs, I even sell a product to generate the chuffs from an encoder tape, the Chuff-Generator.  When you get going at a faster pace, the chuffs do tend to blend together, and I suspect the earlier RailSounds board you picture may handle the fast chuffing more poorly than later versions.

If you want more than 1 chuff per revolution, a reed switch will not keep up. The chuff will skip and sound will not be uniform.

You are correct, won't work.

Chuck, I'll have to disagree with that assessment.  Before I designed the Chuff-Generator, I did a lot of upgrades with reed switches, and I never had an issue with the reed switch keeping up.  I use this Standex ORD324-1015 SWITCH REED SPST-NO 500MA 200V, and I can't imagine the drivers turning fast enough to cause you to miss chuffs.  The operate time is in the sub-millisecond range for any value of magnetic force.  Here's a chart from the spec sheet of the reed switch.

I can't say I've had the same luck. Tried to replace a hall sensor once with a reed switch. The chuff would be erratic and skip. Another potential problem may be very few O gauge locomotives have the clearance between the drivers and frame to mount even tiny magnets to the driver.

I recall a similar issue, I believe you needed to add a pull-up resistor to the switch to the power in order for it to work properly.  It may have been pulling down to ground, I don't remember which polarity it was now.  It wasn't the reed switch, it was the input circuit on the RS board.  RS3 and later just need a contact closure to ground.

I have the original C&O Allegheny 6-28011 fitted with TAS EOB and it does not like 4 chuffs. I’m guessing it’s the railsounds that cannot keep up. If anyone can verify the same let me know. I would love to use GRJ’s unit but may have to gut everything and go ERR components of in fact the railsounds is the problem.

Rod Miller

Since you have the TAS EOB, you most likely have RS4 sound boards.  I've done dozens of those with 4-chuffs, nobody has complained about the chuffs so far.  The issue being discussed here is the characteristics of the hall effect sensor input, not necessarily the chuff audio.