Modify Control System To Run On DC

Nope

So is the engine actually running on a track? 

If you're just looking for the sounds "as if it was running" couldn't you just record the sounds in question and play it back using a sound-module powered by DC?

Or suppose you need low-voltage AC and all you have is low-voltage DC.  This could be posed as a question in the Electrical forum, but I'd think if you only need a few Watts or so of power you could use an off-the-shelf DC-powered audio amplifier module (just a few dollars on eBay) and amplify 60 Hz "hum" to provide enough low-voltage AC power to a PS1 engine so that it creates the sounds in question.

Hey Stan2004!

I am in the middle of a project for a restaurant to deliver food on flat cars.  The equipment is Lionel or MTH engines running on the back and forth system from Dallee.

It controls the engines by DC voltage connected directly to the can motors in the engines.  The engine makes a run from one end to the other at always the same speed.  The sound recording needs to come on at power up, an quit at the end of the line, power off.

I can record the sound files from the original sound board after being removed from the engine.  Listen to the attached Ma4 file.

What you could do is remove the Proto-1 electronics, then locate some DC-based sound modules to replace those with (they use them in #1 gauge equipment). Since the DC-based sound system isn't controlling the motors, you can connect them in parallel to the motor leads and you won't have current draw issues with the boards.

So if it's actually pulling the food (i.e., variable load) using fixed-voltage DC applied to a can-motor, how do you achieve constant-speed since one load may have a lightweight donut while another might have a large bowl of chili with cheese?

Anyway, if it's constant speed as you say, then it means constant-time from one end to the other. I hear the horn and bell so it's more than synchronizing prime-mover sounds to speed.  For simplicity, I concur with Matt's idea of a DC-powered sound board that has a pre-recorded sound that ends with a looping slow speed engine sound so when the power cuts off at end-of-travel it isn't chopping off a "variable" part of the sound.

Now that's the answer I'd give if you're trying to get the job done and move on.  If this were a 'for fun' project, my noisy mind would be shouting at me to add some excitement.  So each run might play a different sound.  Or maybe if pulling a heavy bowl of soup the prime-mover would notch up to a higher rev'ing sound as if struggling to deliver the goods. 

Edit: But what the restaurant patrons really want to see is as follows.  The cook puts too many cheeseburgers on the flat-cars, the engine rev's up to max notch and still nothing happens.  So a helper engine rolls up, couples to the consist and now the food starts moving.  Yes, this is totally impractical (but do-able) but it's the kind action which would amuse kids (and grown-up kids-at-heart)!  This would get customers to tell their friends and get kids to tell parents they want to go to the restaurant waiting for the cook to overload the engine to see the pusher come along. I'd think this was a shoe-in story for the 6 o-clock news - priceless advertising potential!