Would like to know how you have mounted your TIU

I used double faced Velcro tape.

I removed the case on mine so it can be easily removed for changing fuses. Used drywall screws to secure it. 

It is supposed to be best to have your TIU above your layout.  However, mine is just sitting on top of a cart that slides under the layout. It's not fastened, just sits there next to a Legacy 990, also just sitting there. 99% of the time the cart also just sits under the layout.

DCS and Legacy components sit on shelf under control panel.  No TIU removal for upgrade, just bring laptop to TIU's.

Mine is on the end of my bench work, held on by Velcro strips that hold up to 20 lbs. Easy to remove for upgrades. 

If you do it this way, upgrading is easy no matter where the TIUs are placed.  

From The DCS Companion 3rd Edition (page 68) and The DCS WiFi Companion 2nd Edition (page 34):

Sometimes, TIU placement makes it inconvenient to remove a TIU from the layout to upgrade the TIU's DCS software, particularly if the TIUs are placed under the layout, as are mine. To get around this inconvenience, I connected extension cables to each TIU's serial, ProtoCast and ProtoDispatch ports to bring them out from under the table. I also have a long serial ribbon cable that goes from the PC in the train room work area, around the layout to where the TIUs are located. 

When it's DCS upgrade time, I connect the serial cable from the train room to the serial port jumper cable connected to the TIU. I also jumper together the extension cables connected to the ProtoCast and ProtoDispatch ports. Then I can upgrade the TIUs in place, since a little known fact is that it's not necessary to unhook anything other than the serial, ProtoCast and ProtoDispatch ports when upgrading a TIU's DCS software. 

Everything that you need to know about DCS is all in MTH’s “The DCS Companion 3rd Edition!" This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

Everything that you need to know about DCS WiFi is all in MTH’s “The DCS WiFi Companion 2nd Edition!" This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

The Main Power Cart shows two of my four TIUs.  Just untwist the wire slings and lift outl

Thanks for all the replies.  I will be using Velcro as Wi-Fi is weak in my train room and I would need a long cord to get to a decent reception spot.