Newman Atkinson says:

Before you go changing LED’s or the Resistors check and see if there is a CV that adjusts the brightness. I know there can be adjustments for dim when it is stopped and brighter when you begin to move. So there could be a Cv to adjust the intensity too. So check that first.
Do you know if the lights are regular light bulbs or LED’s There may be regular bulbs and have resistors to protect them from burning out. These are my first suggestions.
from Newman Atkinson

Brian Woods says:

This story reminded me of how I got started building model trains many years ago. It was rough at first, I have to admit. I would get caught up surfing the Internet for ours on end for answers or would spend too much time going through the painful process of dealing with inexperienced sales people at my local hobby shop. But somehow I learned to create my own detailed model train layouts without having a big budget or a lot of space, even though I wasn’t good with my hands nor was I an electrician, a carpenter, or an artist. Now me and my two boys spend all our free time with this wonderful hobby. I’m glad that we are having fun together and they are doing something educational with their time.