Phasing

Good question.. I still find it confusing at times but here goes...

As you mentioned  .   Join the transformer  commons together (usually the "U"  connections )

 Try and set  the " hots" on each transformer  handle to around the same voltage.  Say 18 volts.

Now measure the voltage between  transformer  handles , hot to hot... If it's really  low the  transformers are in phase . If around 40 volts the transformers are out of phase.

THE non derailing feature must share the common as the track common....

We're using 8 post war ZW an a KW or 2  so it's a little easier .

What do you have for power? 

We are using 180W bricks., The turnout power is from 16.5 V AC transformers. The common on the derail is connected to the outside rails and the turnouts are run of the same power source, 

Did you try connecting the commons on the 16 volt transformer  and the brick  together?... You won't be able to change the Bricks voltage ,  perhaps  the 16 volt AC transformers as well , Touching the Hots may give a higher voltage  (say 4 or 5)  if in phase but if you get 35 or so they are out of phase....

 Does the non derailing feature work at all? 

Phase doesn't matter if there is no other connection between the  power sources other than the common. 

DennisB posted:

Phase doesn't matter if there is no other connection between the  power sources other than the common. 

True enough.    The 16 volt transfomer's common is just a  long for a ride on the 180ACs common..... .   The 180s should be phased though.

 , If you ever wanted to use the 16 volt transformer for additional track power  someplace it would have to be phased.