Cleaning trains is a very popular subject. If you use the forum search function, I am certain you will find lots of advice.
Lionel used different painting and decorating techniques. So, what will work for one item, might ruin another, even when both pieces were made the same year.
The general rule of thumb is be gentle, don't scrub.
Dishwashing soap and warm water is OK for most items.
I don't even blot my trains dry. I shake them off vigorously, and hang them from a piece of wire to dry.