Joining 2 small layouts?

This should be a relatively simple task.  Physically the track will mate up.  Then you just need to ensure the two transformers are phased correctly and the center rail connection at the point they come together is insulated.  Then if he wishes to move from one to another he should check the power to each side is similar to avoid surges or abrupt stops.

Are the two layouts physically close enough to one another as to where they could be connected to one another ?

What type of track are you using on the layouts ?

Are they the same height?

Absolutely it's possible!  You have to make sure the diameter of the divergent (curved part) of your switches matches the diameter of whatever curves on the layouts you are replacing, and add a short "bridge" section of lumber between the layouts.  All 3 rails on the bridge section (sections if you add a second bridge to return to the other layout instead of backing through a single bridge) should have an insulation gap, simply cut through the rails with a dremel.  You can also use a Realtrax insulated section, just make sure there are no jumper wires joining both halves underneath.  This gap will keep your transformers on separate circuits.  Make sure both transformers are in phase, my Z750 has has one wide blade on its AC plug, I'd assume the Z1000 does also, I don't have one so check to be sure.  To go from one layout to the other, just match the speed of both the Z750 and the Z1000, say both transformers are at half throttle, and your train won't even notice when it goes from one transformer to the other.  This is for conventional operation only, I don't have DCS and it may have to done differently if you use DCS.  Good luck and have fun running with your son!

~Larry

Okay - so you're using RealTrax. You basically want to set up the layouts so that there are switches between them that allow you to travel from one layout to the other and back again. The attached diagram shows different configurations of doing this, depending on how close the layouts are to each other and the center rail to center rail spacing. It is for Lionel Fastrak, but the principle is the same for RealTrax.

You will need to buy four (4) of the same diameter switches and possibly two (2) small "fitter" pieces, like RealTrax 40-1018, to go between the switches. As was said before, you will need to make a small cut in the center rail, typically in the "fitter" piece so that current from one layout's transformer does not "bleed" into the other layout and you can operate the layouts independently.

When you want to switch, make sure the transformers as close as you can get them to putting out the same voltage and make sure the transformers are in phase.   

Thanks guys, this is all helpful and great information. I guess a couple details I should have added:

@ogaugenut posted:

Are they the same height?

Yes both layouts are the same height.

@Richie C. posted:

Are the two layouts physically close enough to one another as to where they could be connected to one another ?

What type of track are you using on the layouts ?

Both layouts are Real Trax, and they are close enough to link. This might sound stupid, but when we moved to our current home, I built my layout on wheels, because of other plans, I knew it was likely I might need to move it. My son's is on wheels also so I actually moved them into place today. I'll get pictures tomorrow of how its set up. 

I have a pair of switches I'm not currently using so it sounds like I'm well on my way to making this a reality.