I've decided to take the plunge!

Reply to #3: Purchase a NEW Legacy 990 system with full warranty. When I had to send mine in for repair they wanted a receipt from an authorized dealer included with the RA. I think it's also Lionel policy, but my local Lionel authorized tech told me it had to go back to Lionel for repair, all he could do to them was upgrades. Upgrading the base was the problem in my case, it would not upgrade. To me the warranty is worth it. In the past, I have heard Lionel honors the 990's warranty when it is long past the expiration date, but I don't know if they are still doing that?

I don't know what cable you now have for your TMCC base to TIU connection, but you will need the #50-1032 cable from MTH. I think this one was revised for Legacy and is the latest version. I don't think the older TMCC cables work with Legacy. If you control all your MTH with DCS and all your Legacy/TMCC with Legacy you don't need the cable, that is how I am currently set up and don't use the cable. I don't know about the Zstuff data driver and cabling required for that?

The Legacy 990 system is great. No problems have migrated from TMCC to Legacy. Well supported by Lionel. Version 2.0 just came out and very easy to uograde. Smart Phone apps available to run them off of iPhone, Ipad as long as you buy the WIFI module. This WIFI module is out. Upgrading is easy as long as you can get a rewritaable blsck module. I purchased a few to make my life easy. Down load the program to your laptop, upzip and the Legacy Utility Application opens up. Connect the cable provided (MTH you need to go buy one, not included) to the Legacy Base, make the modules and upgrade the remote and the legacy base/

DCS, good too, version 5.0 came out. You need to upgrade the remote and TIU to allow for MTH's version of WiFi. This WIFI module, last I heard, was to be release sometime in December 2015 / January 2016. Down load the software from MTH. You need a 9 Pin Serial cable, phone cord and jack, ALL IN THE INSTRUCTIONS BUT NOT PROVIDED, follow the directions and upgrade as required.

If you do it correctly, print out the directions, it takes about 30 minutes max to do this and your home free. I have never had to send mine into the respective service folks for assistance. They have service and support numbers if you get lost in the upgrade plus their are plenty of MTH and Lionel Service folks on the forum to help out. 

At the NJ Hirailers, we operate the entire layout with DCS and TMCC / Legacy. We dont have cables tie to the TIU or the Legacy base. They are independent and operate differently.

At my home, I use both as well. The only item is the ground cable from the base to the track. Not real sophisticated but it works.

Look at Rich Battista's - The Black Diamond RR as he covers dual operation and if you need a book, buy Barry's new one that just came out - He appears to be the MTH Czar

I run DCS now and have the MTH cable connected to TMCC.   I have to agree going brand new is the way to go.  Mario's trains has the cheapest I've found at 299.00 with free shipping.  Anyone else cheaper?

Super W 1,

    Purchase the Legacy Brand spanking new from an authorized dealer, get the Warranty.  Forget the used Legacy.

Merry Christmas!

PCRR/Dave

Done, just ordered from Mario's trains.  Now if I can find the funds for the Empire Express Hudson coming out soon.

For what its worth, I would buy new if possible. Keep and make a copy of the receipt, and the dealer name and address.  Also, I would use the cable with the 990 set and have it TMCC and Legacy equipped. I am not an authority on the DCS System.  Lionel has always upgraded my Legacy System, No Charge, other than the UPS I spent sending it to them. The remote is great, the possibilities are simply Endless....Simple to use, and best of all TM Video's has a really nice instruction video for our Learning Curve, for Senior Kids.....WOW...Go Legacy!!!