The minute your train set left the shop it was worth half of what you paid
for it. An initial bid on eBay is likely to be half as much again. If you
set the opening bid any higher than that you are unlikely to receive any
bids at all. Pick a closing time for the auction when many modellers are
likely to be on line. Saturday morning is good as also is Sunday evening. In
my experience bids don't increase significantly after more than seven days.
That also makes it very easy to select the start/finish time. Check if
someone else is auctioning a similar item. You can often steal a bid by
undercutting them on postage even if it means taking a slight loss. Bring
the date forward too if that means your item will sell sooner than their's.