The K 'n G Railplex is a high-action train layout showcasing four to eight trains running automatically on a single track. The trains present a unique visual experience by starting and stopping, changing speeds, and taking different routes through track switches, all without operator attention.

The layout has four loops: outer, center, inner, and work. The "outer loop" has an "operator siding" that is used to add and remove trains. The center loop has a "bypass track" that also has a siding. There are 234 feet of hi-rail track with O-54, O-72, and O-96 curves. There are twelve Lionel O-72 switches, mostly 711 (prewar) models. The platform is 10' 2" by 18' 10" assembled from eight portable panels.

The layout is operated as a "block system" with thirty-eight independently powered blocks. A track outside rail is isolated and used to "detect" when any part of a train is in a given block.

A train is stopped if the block ahead is occupied by a train; it proceeds when that train has moved out of the block ahead. A train will run faster if two or more blocks ahead are clear, slower if it is closely following another train.

The twelve track switches automatically route trains to the layout's four loops and into the two sidings. Trains waiting to be routed through a switch are randomly selected. The outbound route that is most clear of other trains is chosen. If all routes are clear, then the outbound route is selected randomly. The operator can change the automatic route selection so that one route is preferred over another or can manually direct one or more trains to a selected route. Thus, the operator is a "dispatcher," rather than an engineer.

Operation is fail safe. If a car becomes uncoupled, following trains will stop before entering that block. If a train derails, power is removed from that block until the derailment is corrected, but trains in other blocks still run. No modifications to postwar Lionel engines are required.

A relay for each block switches power on and off as directed by routing control boards. The routing control boards use the isolated outside rail to "detect" when a train moves into a block and to check if the following block is clear. Each block is controlled only using the "detect" signals from adjacent blocks; there is no master control computer and no special computer programming is required. Accessory control boards activate the twelve switches, turn block lights on and off, and operate gateman and other features.

The K 'N G Railplex Train Layout was designed and constructed by John Kerklo (TCA 94-38455) and Tom Greene (TCA 93-36997), both members of The Rocky Mountain Division of the Train Collectors Association.

The mechanical design of the K 'n G Railplex started with clearly stating goals and then making trade-offs and compromises to achieve a practical train layout. A lot of design trials resulted in a panel arrangement and track design.

Panel construction included making truss pieces, building the trusses, assembling panel frames, and then attaching the track surfaces to the panel frames.

The next building phase was laying track, cabling to interconnect the panels, building controllers, and wiring track, train power, and controllers.

Next came thoroughly testing the K 'n G Railplex.

Running multiple trains on a single track presents powering requirements decidedly different from running multiple trains on separate tracks.

The layout was originally powered by four Lionel KW transformers, four Lionel ZW transformers, and one Mainline Industries "The Max" transformer. A Mainline Industries "Sub-Station" Transformer powered lights and operating accessories.

Weight was a problem. The array of transformers pictured weighed over two hundred pounds; too much to conveniently lift into the bed of a pickup truck.

The train transformers have been replaced with two custom wound "tap" transformers.

The K 'n G Railplex is portable and is displayed at local train shows. Far more train enthusiasts see the layout than a permanent home layout. The downside of this portability is that the layout, trains, and everything associated with the layout must be transported to the train show.

Click the image to see how it is done.

You can see The K 'n G Railplex in operation at most Rocky Mountain Division, Train Collectors Association, shows. Check out their web site at RMD/TCA for show schedules and locations.