Mark,
There is one caveat of which you should be aware.
In order to operate correctly, each DCS engine must have the same DCS ID# in all DCS Remotes in which it is present. If not, the engine will not operate correctly.
This may be assured by always adding a DCS engine to all remotes, sequentially, one after the other.
This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!