ge_rik
British narrow gauge (esp. Southwold and W&LLR)

I'm always surprised at the cost of those little sound units providing ambient effects around the railway (c£40). Being a bit of a cheapskate, I've made my own (£10) - though I've now seen even cheaper ones on eBay at around £3 each. Here's what I did
riksrailway.blogspot.com
How I created lineside sound effects
Narrow gauge large scale model garden railway. Battery powered, radio controlled locomotives, some Bluetooth. Set in Cheshire UK in 1930s