Hello iTrain.

You might have noticed that we do have a For Sale sub-forum here on the site.  There may be members here who would be interested in your Trains and you wouldn't have the associated pa_pa_ or e-ba_ expenses.
There are other train sites that you can post your items for sale for free.

Shipping your trains can be done by USPS, UPS, Fedex. 

I tend to use USPS to ship with, they have a shipping cost calculator on their web site.  I've shipped some quite large & heavy boxes at very reasonable costs with them. 

After the sale, the choice of shippers should  be between you and your purchaser.

Dave