How would the levers be labelled on the two levers (1 &2 say) for a double slip on the up line that is used as a crossover between up and down mainline and into a siding.
With both levers normal, the routes are straight through, lever 1 reversed 2 normal is the crossover between up and down, lever 2 reversed and 1 normal is up main to siding. It needs 1 and 2 to be reversed for down main to siding.
Dezzi.