I'm looking for a method to protect a scenario where there is both a double slip and a pair of single crossovers. It exists in a nice yard on the DLS. Yardwork http://www.trainsim.com/vbts/showthread.php?310400-YardWork! if you look at the 3rd picture down it shows exactly what I mean. The existing signals work, but do allow for whatever its called when 2 trains run through each other. I have boats products (ASB turnout etc) but I cant seem to figure out how to both protect AI drivers and allow what I want. I've created a fictional modular route I can then merge with other routes to get a totally make believe way of sorting etc. In my little route all traffic enter through 1 of 2 portals (iportal or regular) and eventually enter this "Yardwork" portion used for staging. It then continues on for hump duties, engine work car repair etc and finally out through a portal or iportal to rejoin the real world. BUT, in the example shown there are 16 inbound tracks, 8 per side. I have them set up as 1 - 16 and I use a trackmark list so that any incoming train will go to the next available track. Works great except when 2 trains come in together and cross over each other. Again using the 3rd picture in that link, how can I make it work for AI traffic? payware or freeware, its only for me.