Impossible to say without detailed pictures. Many subversions were made that can significantly influence the price. Condition is a major factor. So is the presence or absence of the original box, booklet, etc.

As noted above, condition is critical.

For a general idea of what the Locomotives are worth, do a quick Google search on sale sites.

General rule of thumb when it comes to selling 'antique' items:

1) If you want/need money fast, a toy dealer will pay you cash up front fast. However, he will be paying you wholesale prices for the items: You will be getting the lowest ammount for your items.

2) Ebay is a fast way to 'let the market' decide what your items are worth. There are always sales strategies to be used, pictures and reasonable opening bids will help get your items sold.

3) Auction houses dealing with model trains. You consign to them, they get a percentage of the final sale price. This will take a bit longer but usually yeilds good ($$) results provided you have good items to sell to begin with.

4) Direct sale to a collector. You should make more in the deal than if you sold it to someone who owns a store but less than its full retail value. You might be paid in cash, which is always good.

Note: The 3015 is a Marklin fan favorite. They were expensive, and lower production, units when sold originally. So, you should be in a good bargining position with the Croc.

As you can already see, there are folks on this forum that would love to see the pictures of your items.