If you’re using normal track power, Then Tony’s initial response of “no” is spot on.
But you could still take out the motor : -)
You could muck around with electronics, but I don’t think a movie would be worth all the stuffing around.
But if you just wanted to do it temporally, just for a movie, you could possible do this.
Before I tell you what I’m thinking let me tell you this. I do have a Bachmann K-27, I haven’t had the time to re engineer the thing yet so I’m not 100% sure of the internals.
If the take the coal load off the tender, and removed the top circuit board of the “Super Socket” two of those pins on the fixed board should be the terminals to the motor (well that’s what you normally get). So now that you have the two terminals to the motor you could just stick a battery to it and it will just run at a constant speed, which maybe all you need to do your movie? And when you have finished with the move just disconnect the battery and stick the circuit board back in.
Doing the above you don’t change the loco, and you won’t need any flash controlling circuits, just a cheap battery, maybe a 6V torch battery??? This is a bit backyardish but it may get you what you want?
Someone with more experience with the K-27, is what I’m suggesting possible? Or are the motor terminals hidden amongst a sea of circuit boards and other unnecessary electronics?