From the 'Why do Bulleids slip?' thread: ????!!!!! I think that you are getting somewhat confused here.... Track circuits don't provide detection for points - that is done using point detection, regardless of whether the area is mechanically, TCB or axle counter controlled. A signal can just as easily be interlocked against a track circuit or axle counters. A track circuit doesn't do any more than detect the presence of a train on a section of track, which is what axle counters do. Maybe we need a new topic on this now![/quote:13fy1dbx] Not quite true, track circuits will lock points (hence why we have sealed releases at some locations) and will operate other kinds of signalling equipment for example signals that are released by approach control or are approach lit will be worked by the presence of a train on track circuits. Another topic in a signalling section might be more relevant for this.[/quote:13fy1dbx] Are you confusing axle counters with treadles? An axle counter counts the number of axles into a section of track and it will then show as occupied until all the axles are counted out of the other end of that section. While the section is occupied, points can be locked, routes help, signals approach control, or whatever else. A track circuit will show as occupied once one or more axles enter its section, due to the axle dropping the track circuit relay at one end. It will remain showing occupied until all axles are cout of the other end, allowing the track relay to pick up. While the section is occupied, points can be locked, routes help, signals approach control, or whatever else. Both systems are methods of showing a portion of track as being occupied - they deliver the same result. The difference is in how they can fail! And factors like track circuit clips not having any effect on axle counter sections. Neither track circuits or axle counters provide detection for points - that is proved using point detection boxes before a route can be set up. Track circuits AND axle counter may both be used to hold a route over a set of points once set up and once occupied by a train.