Hi, paigetrain Welcome to the Forum
Beginning in 1970, Lionel trains manufactured by MPC (Model Products Corporation, a division of General Mills, the breakfast cereal company) have "Fast Angle" wheels and needlepoint axle bearings. They roll much more easily than Lionel Postwar cars (1945-1969), so they are a good choice for long trains. All of them couple together, and their variety approaches infinity.
I like Lionel FasTrack so I recommend that. Use "072" or wider curves for smooth, fast operation. Switches are non-derailing.
Two books will be a great help: The Lionel FasTrack Book and Lionel FasTrack Model Railroads. They deal with wiring, layouts, and building scenery. They offer all sorts of helpful tips.
For easy operation of long trains, a yard could branch off either side of a main line by using "ladder" tracks. Connect both ends of sidings to the main line. Then one train can be stored on each siding and run onto the main line when another train enters a siding.
A main line can also go through the center of a yard. "Ladder" tracks and sidings can be placed on each side.
Lots of possibilities.
I'm certain you will receive many useful replies.
Buying a set is one option. But so many locomotives, cars and accessories are available that I recommend looking around. Perhaps your friend, Bridget Atland, will come across a train for your railroad.
Come to think of it, you could make an Office Car Special (OCS) for officials of the APWR. Get some passenger cars. Send then to CJB Custom Painting & Designs. Settle on an "official" paint scheme. Christine J. Braden will do a beautiful job. I'll post photos of Walter Matuch's RMT (formerly K-Line) AMTRAK streamliners that she painted to match my 2348 Minneapolis & St. Louis GP9. Ms. Braden also paints locomotives, freight cars, and cabooses.
Name one car BRIDGET ALTLAND.