Hi Willygee,
If you have a smart device with Bluetooth (cheap Android tablet, under $60) you can use a free Android app
https://play.google.com/store/...eator.free&hl=en
that is a sound board application. It will allow you to play several sounds at the push of a button on a touchscreen through to a Bluetooth speaker on your layout (or a speaker on / in a moving piece of rollingstock), and you can have the sound file repeat as long as you'd like.
Audacity is a great free program for Windows that will allow you edit your recordings. If you get clean enough edits, when the file loops, it can sound seamless.
http://sourceforge.net/projects/audacity/
I don't know if the looping from the free Android app has any kind of a split-second delay between looping, but there are other sound board apps for smart devices, some free.
If you don't mind the Android being tethered to the speakers, you can skip the Bluetooth thing.
Good Luck!
Take care, Joe.
(edited for typos)