It has been interesting TAS and Digital Dynamics supplied some pretty good kit/instructions to do upgrades from conventional/or even early electronics to TMCC, and eventually EOB/which was TMCC with speed control.
ERR has upgrades still available to TMCC.
I don't think there are upgrades to Legecy, at least not yet.
As I said it was interesting. You could purchase a relatively good model, inexpensive, and add/or have TAS add, some really decent electronics. One of the really cool upgrades, I know it's not prototypical, was the reversing marker light done with bi-directional LED's.
What got done. All have sound, most have electro-couplers, and some lighting detail.
Pennsy GE 44 tonner, Rich Yoder. A Small ERR conversion kit with electro-couplers.
(2) Atlas Dash 8 40 BW's Had TMCC, SAW Gen2 boards, both were upgraded to EOB
(2) Weaver Union Pacific Alco C630 TMCC SAW board upgrade with marker lights and electro-couplers. Eventually I did a second C630.
Weaver Pennsy H10 was an EOB upgrade done by TAS with Electro-coupler.
Weaver Pennsy L1s Was done with a TMCC SAW upgrade, and then again to EOB with electro-coupler, the original TMCC SAW upgrade was tweeked and installed in the second C630.
Weaver Pennsy G5 was done with one of Ed Bender's Digital Dynamic kits, Electro-coupler.
Weaver Pennsy A5 was also done with a Digital Dynamics kit. Most difficult fit with couplers front and back.
Weaver Pennsy M1a Mountain was done with an EOB kit by TAS with electro-coupler.
Weaver Pennsy C1 0-8-0 EOB with electro-couplers front and back. Required a motor change out from Frank Timko.
Weaver Pennsy U25B EOB kit with marker lights and electro-couplers .
Weaver Pennsy E8's pair. Both units got EOB upgrades with marker lights and electro-couplers. Also required a motor change out from Frank Timko.
As I said it's been interesting. I have a Third Rail E6 and I10 I would like to upgrade to EOB. I have used EOB mother boards and the appropriate Lionel R2LC boards, Sound power and Sound boards, but need a source for the optical sensor parts. Any ideas would be appreciated.
Do I need Legacy? Probably not in the near future.
Best wishes,
Mike CT.