The National Train Show is held in conjunction with the NMRA Convention, but it is organized by a different group, and not the Portland convention committee.
More information can be found on the NTS web site at: www.nationaltrainshow.org
Some useful links have been included here:
For National Train Show booth rental information, contact Kristy at: firstname.lastname@example.org
To request space for National Train Show Modular Layout Packet, contact Kristy at: email@example.com
Details on how you can become an exhibitor can be found on the NTS web site: http://www.nationaltrainshow.org/2015/NTS_Vendors.html