MIKE CT:
Relay Board for controlling turnouts and track blocks
I have built a relay board to be used with my MTH AIU. However this relay board is general purpose and could be used with the Lionel system or any other control system.
This relay board contains individual power relays. See attachment.
The purpose of these separate relays is to limit the current through my MTH AIUs to about 1/2 ampere maximum. Therefore the current necessary to control a turnout or power a block is provided by the separate relay and NOT the AIU. The Relay Board is designed to connect to my AIU Patch Board. (See also attachment)
Note: Every relay "circuit" is protected by a combination of circuit breakers and fuses including all turnout solenoids. Each track "block circuit" is also individually protected in case of a short circuit or overload. This means that any individual fault anywhere on the layout will be detected and cleared without affecting any other circuit.
The second photo shows my AIU patch board. It is a convenience termination board that interfaces with the relay board. Note: Two AIUs are shown. Each AIU can control up to 20 circuits.
