jlehmusk

From what read from the other Duplo train thread I understood that new locomotives don't have the sensor at all. I personally would open and clean it. Some instructions can be found here: http://www.cailliau....in/Locomotives/.

Robert, your Lego pages were really interesting to read. Please keep the updates coming. The problem can be solved with directed graphs. Each straight section can presented with two nodes. One for each direction of travel. A switch is 6 nodes and 4 edges. It's quite trivial to construct the graph for the whole track from these subgraphs. These examples are refering to figures on your math page: With this presentation the APR problem becomes SCC (=Strongly Connected Component) problem of directed graph. In APR track there only one SCC. There are many linear time algorithms to count the SCC's. Please see http://en.wikipedia....ected_component for details. This doesn't exactly solve your problem 2, but it offers an another aproach with a proven linear time sollution.