Most garden railways have a fleet of several locomotives but only run one or two at a time. Fitting soundcards to all of those locomotives can get expensive and you may be looking for an economical and simple way of adding sound to your railway. The solution may be a soundvan. You select a car, van or wagon which would commonly run behind the locomotive, fit it with wheel pickups and install the sound as shown below. You can then readily use the remote control to adjust the sound to match whichever locomotive it is running behind at the time.
Building a simple soundvan for analogue DC track powered railways