Yes they are good , but they are payware so you need to purchase before hand. This can be done with ATLS and the inverse slave. This set up can be used with any signals, even the scripted ones.
ASB Crossover is freeware on the DLS and is designed for use where 2 (or more) lines cross, exactly as Deighton describes. It controls the 'crossover' so that one train will stop, and without any SPADs occuring. See http://www.boatztrainz.co.uk/asbc.html
ASB Turnout is the payware item available on my website or by clicking the banner below. This does a similar thing at a double track 'turnout' but also controls the turnout points and again without SPADs.
