lionel legacy issue

You could try reloading the Legacy modules, only takes a couple minutes. Are you sure you are setting the engines to the correct Engine ID as well as the Legacy unit?

May be a stupid suggestion but I recently had some lack of response, I checked each Cab 2 battery's voltage  and replaced with all new ones.  Worked fine afterward.

and making sure they have plenty of tension on the battery contacts...

Will try suggestions.

Thanks, Liam

A couple of other things that may help.  You may wish to check that the antenna on the base is firmly attached, is upright and not touching anything.  There is a reset button on the remote. There's a little hole on the underside that you can push a blunt toothpick, straightened paperclip or ballpoint pen into. Don't use anything sharp or too pointed, and don't press too hard, you don't want to damage the switch.