The Two Crossover Loops automated track plan shows a long track loop "folded" into a smaller layout space using a track crossover. The crossover also serves to pace the trains so that one train isn't always just following another.

The example layout has ten track blocks. Trains move clockwise, in the direction shown by the arrows.

The layout will run three trains quite nicely.

This layout is powered with two train transformer circuits. Transformer circuits may be required to power two trains at once.

The automated layout is implemented with six "Train Block Controllers:" two in "One Block with Power Passing" configuration, three in "Two Track Blocks" configuration, and one in "Crossover" configuration.

Each of the ten track blocks is assigned to "Block One" or "Block Two" for the TBCs. Following shows assignments for each track block.

The isolated outside-rail for each track block is connected to the outside-rail input of its assigned TBC.

The isolated outside-rails of crossover leading and trailing track blocks (L1/T1 and L7/T7) are connected together and one wire connected to the controller outside-rail input for each. (One wire from L1/T1 to the controller and one wire from L7/T7 to the controller.)

The isolated center-rail for each track block is connected to the power relay of its assigned TBC.

Crossover leading track blocks are connected to the power relay, but corresponding trailing tracks are not connected to the power relay. Trailing blocks are always powered, with connections shown a few tables following.

The assigned train/center-rail transformer post is connected to the power select relay for track blocks controlled by TBCs in "One Block with Power Passing" configuration and to the power relay for blocks controlled by TBCs in "Two Track Blocks" and "Crossover" configurations.

For TBCs in "One Block with Power Passing" configuration, train power from the "FOLLOWING" track block is connected to the select relay and the "select" relay is connected to the train power relay for the track block.

Trailing track blocks (T1 and T7) and the crossover are always powered. These track elements are connected to the power source that is powering the crossover leading track blocks. The crossover track section is powered by steel center-rail pins to the trailing track block sections, or by a wire connected to the crossover center-rail, or both.

A given "Train Block Controller" communicates with adjacent track blocks to know if a train arriving in a track block can be powered. Track blocks adjacent to a given controller are designated "PREVIOUS" and "FOLLOWING," relative to train direction. For a given track block, a train has passed the "PREVIOUS" block, and proceeds to the "FOLLOWING" block. In the diagram, block 1 is "PREVIOUS" to block 2 and block 3 is block 2's "FOLLOWING" block.

Each controller block employs two signals for controlling trains in track blocks. Train-In-Block (TIB) is set when a train is in the controlled track block. Train-In-Following-Block (TIFB) is examined to determine if a following block is clear and a train can proceed. For each block, TIB is connected to TIFB of the controller for its "PREVIOUS" block. TIFB for a block is connected to TIB of its "FOLLOWING" block.

TBC controller interconnections are listed in the following table.

The next automated train layout builds on the Two Crossover Loops layout with the addition of two track switches and a passing loop, implemented with "Train Block Controllers" in "Automatic One-to- Two Track Switch" and "Two-to-One Track Switch" configurations.