Legacy on 2 Rail?

Wow.  Not sure it would be simple at all.  

If you manage to do, it be sure to both post it here and do an article in OGR magazine about it!!!

Just based on what I know (and others hopefully will chime in on this who have far more knowledge).  The big thing is isolating the wheels from each other, then rewiring electrical pickup to be on one side while the other remains the negative return, might also involve internal wiring depending on how they bring negative to the engine)

In terms of legacy working, it should work fine with 2 rail if the conversion works. The actual signal is sent through the house wiring, so that doesn't change, as long as the track wire is on the negative rail and is available in all areas of the layout, should work from what I know. I suspect the devil is in the details with this, trying to isolate the wheels is likely to be a bear, especially the drivers. 

No problem with Legacy on 2-rail, just look over the fence at the Legacy Flyer models.  This should work right out of the box.

Well if TMCC works fine on 2 rail, I can't see why Legacy would not? Doesn't it already exist for American Flyer S scale stuff on 2 rail?

Look at the pages from Carl Tuveson for info on that.

Converting some Lionel O stuff to 2 rail is not easy IMO. I think it depends on the exact engine and model? I have converted their rolling stock fairly easily.

Just be aware that I think most O gauge 2 rail systems are DC. TMCC/Legacy require AC power. That said, nothing but time, money, and similar resources stands in the way of providing AC power on 2 rail O gauge track and adapting the locomotive accordingly.

Those old Weaver or Atlas 2 rail models are perfect as the whole China drive motor drops right into the Lionel frame and the wheels are already insulated plus there is a pickup on the insulated side. I have 2 of these in my collection that are basically for parts.  By taking the motor and drive train out, placing them on the Lionel frame and soldering the pickup wires correctly, I have a lovely 2 rail Lionel diesel with Legacy. I know others have insulated the Lionel wheels and have had mixed results but the old swaparoo is tried and true as long as you have a donor.  Because Weaver is now in the dust bin of history, getting the 2 rail China drive units may be a little difficult.  Atlas still uses them though so I may investigate their availability if I move forward in buying one of the new Lionel geeps or sharks.  Thanks all, I forgot Flyer was using Legacy these days.  Sounds like I am in business.  I will post photos when all is complete and I have not blown up the train room.

Calling @John Sethian: He can instruct you all about successfully converting 3-Rail Lionel to 2-Rail and running Legacy on 2-rail (which shouldn't prove any issue at all).

Legacy works just fine on two rail, many of us S gauge operators use it. There is one thing you want to which is put the signal on both rails for better performance. That is done with small capacitors per the drawing below. Also do not forget about the need to wire reverse loops correctly and the possible need to separately power the turnout frogs if they are metal.

Good stuff everyone!  Looks like Cadillac Mike has a really cool autumn project in the wings. And I thought my layout was just about finished.....

One challenge is that the Legacy electronics themselves (including the flywheel encoder ring and tach sensor) are not marketed as an upgrade kit.  You have to order specific parts, or cannibalize them from a donor locomotive.  In some cases Lionel restricts part availability for warranty purposes.  A few 3-rail Legacy products eschewed the optical tach sensor in favor of using back-EMF for closed-loop speed control.  The results weren't as good and some customers complained.

If you broaden your considerations from Legacy to Lionel's TMCC command environment, you could use the Electric Railroad (ERR) Cruise Commander decoder, which also uses back-EMF for speed control but is well-liked.  It's still a proprietary solution (Electric Railroad closed about 18 months ago and 3-railers held their breath until production was taken up by Sunset/3rd Rail.) 

Not really sure what you stand to gain with this approach.  If you invite friends over or take your locos to another layout, you would have to bring your command gear and hope it's inter-operable with whatever system they have.  Personally if I were in 2-rail, I would use one of the established DCC systems, or make the leap to direct R/C with a system like Airwire* or RailPro.  (*Not necessarily battery power, but R/C direct to the loco, should be compatible with any existing system.)  My $.02.

I just got an alert to this thread..

No problem running Legacy or TMCC with 2 rail.    Hook the legacy (or TMCC) base to the ground rail as you normally would.   You will need a Cab-1L and Base -1L to run the Legacy and TMCC locos.  A regular Cab1 if you are just running TMCC.   With the Cab1L you will have all the needed functions (horn, bell, lights, speed control, smoke, crew talk, etc.)   If you want all the features you will have to get the full #990 Legacy System.

No problem running either Legacy or TMCC on the same layout and the same time as DCS.  I have done both.  I do not go through the DCS TIU for the hookup, but you can. I just prefer to use the Lionel Cab for Lionel locos and DCS remote for DCS locos. 

I have no experience running ERR, but I imagine its the same as the above

I have no experience running TMCC/Legacy with DCC. I would guess there are compatibility issues

TMCC/Legacy or DCS with DCC is a non-starter as a rule.  The waveform of the DCC track power/signal chews up the carrier of either of these control systems.

@Ted S posted:

One challenge is that the Legacy electronics themselves (including the flywheel encoder ring and tach sensor) are not marketed as an upgrade kit.  You have to order specific parts, or cannibalize them from a donor locomotive.  In some cases Lionel restricts part availability for warranty purposes.  A few 3-rail Legacy products eschewed the optical tach sensor in favor of using back-EMF for closed-loop speed control.  The results weren't as good and some customers complained.

If you broaden your considerations from Legacy to Lionel's TMCC command environment, you could use the Electric Railroad (ERR) Cruise Commander decoder, which also uses back-EMF for speed control but is well-liked.  It's still a proprietary solution (Electric Railroad closed about 18 months ago and 3-railers held their breath until production was taken up by Sunset/3rd Rail.) 

Not really sure what you stand to gain with this approach.  If you invite friends over or take your locos to another layout, you would have to bring your command gear and hope it's inter-operable with whatever system they have.  Personally if I were in 2-rail, I would use one of the established DCC systems, or make the leap to direct R/C with a system like Airwire* or RailPro.  (*Not necessarily battery power, but R/C direct to the loco, should be compatible with any existing system.)  My $.02.

Hi Ted, thanks for the "heads up" on the conversion to Legacy. I do have some ERR kits in my stock and will probably start with one of them on an old Williams brass 2 rail camelback and ease my way into Legacy if I can.  I do have a number of actual 2 rail DCC equipped locomotives that I can always use if need be but I have always liked the MTH DCS stuff because I am a little clumsy at times and having a "close to scale" locomotive is ok with me rather than a super fragile brass or plastic loco that I manage to bend due to my meat cleavers.  I live out in the sticks and work in healthcare so at this time "friends" and "visiting other people" are kind of foreign since everyone seems to think I will give them the 'rona.  Since my pike is only 4 X 12, I do not have a huge roster nor do I have anything larger than a 4-6-0 with blind center drivers. The MTH 3-2 stuff runs great on vintage Atlas 24" turnouts and track and I had the DCS set up and 3 lovely MTH steamers from my last pike, a three rail affair.  I am one of those guys with very limited space that did not want to model only "traction" in 2 rail and with 24" radius, my options were limited so the whole MTH/TMCC set up was attractive.  I appreciate your great advice, it is always nice to have a professional opinion before I butcher up a perfectly good specimen.  Why make hamburger out of a T-bone steak....👍

Mike