No, but I can make one. 
You can use one power bridge as long as everything has the same polarity. Relays can be used as simple switches to connect/disconnect the output from the bridge, to different blocks. The wiring is extremely simple, just use the relay as a switch. However, if you're using this to control train speed, you can't start or stop them with momentum (slowly).
In traditional model railway wiring terms, you are just making a DC cab control system, but with only one cab. The signalling is a different matter. It looks like you would need a hybrid system with inputs from the cab and track occupancy devices.
The way you've specified this, in a very unique way, you probably won't find any exact examples to copy. Most people now are just using off the shelf controls for such systems, because it's more straightforward and easier to find help.
There is a forum search box at the upper right hand corner of the page.