Across the top you can see the Detector Cards. They are the ones with the blue circle
and white tags beneath. One for each block. They detect current flow and tell the
computer something is in this section of track. This is also reported on the Dispatchers
board as a yellow occupancy light. This informationis also used for block assignment.
The Cab Relay Cardsare the green boards with the black relays and green circles.
There is one of these cards for each block.. There are 7 relays on each card, one
for each throttle (Cab). The red leds show which cab is connected to that block at
any given time. When you or the computer assigns a block to your cab, this is where
it happens. As the train moves from block to block along the railroad, the computer
assigns the appropriate blocks, based on availability and direction of travel.
The horizontal board with the black rectangles is for switch machine control. There
is one chip for every mainline turnout on the railroad that is controlled by the
Dispatcher. These make it so the Tortoise switch machines can be thrown by an input
from the Dispatcher board.
The cards with yellow, green and white wires are digital input and output cards.
An input is when a switch or button is pushed, an output is the action to carry out
that command. The first board is the serial board, all the information from and to
this area is packed and sent to the computer for processing on a 3 wire cable!
The area to the left and behind the wood post is the signal board. This is where
the commands from the Dispatcher for a specific signal designation are implemented.
This component board is repeated at Niles in a parallel configuration. This is because
we also feed the Dispatchers board from that location, which doubles the I/O boards
needed. There is also a smaller version located in Salt Lake. All this is managed
with an old 386 computer. All the boards were assembled and tested on site.