Marx had a huge amount of variations in what they did and poor record keeping. The same trains got made for decades. Some for around 50 years with only minor changes.
Good photos of the whole train (and other contents) out of the box would go a long way in helping us know exactly what you have there. ( and starting a fresh thread in the tinplate forum will be seen by more folks. Once you type, you'll see an attachment tool in that composing box, lower right, in blue text.
When you decide on a price, you can start a for sale ad here...free. Selling "bid style" with no price is forbidden here for lots of reasons
We are all interested..... in seeing it, if nothing else