Adrian, thanks again. I really appreciate your insight on these questions. Just to avoid any possible misunderstanding, do you see the benefit of doing what I'm proposing which is:
Given a non-DCS layout, installing TVS diodes on both sides of locomotives' electronics (motor side and track side) as well as across transformer outputs and any other accessories using solenoids or motors?
Putting a TVS internally across the motor will have no effect on any command signals, DCS or TMCC/Legacy. Obviously, if you don't now, and never intend to run DCS, then you can sprinkle those TVS diodes anywhere you like.
To paraphrase: "What happens inside the electronic package stays inside the electronic package". 
One issue with a truly huge ton of TVS diodes all over the layout. Although they don't fail often, they do fail. If you have twenty TVS diodes distributed around your track, eventually you will have a failure of at least one. Tracking it down might be a bit time consuming.
@SteveH posted:Adrian, thanks again. I really appreciate your insight on these questions. Just to avoid any possible misunderstanding, do you see the benefit of doing what I'm proposing which is:
Given a non-DCS layout, installing TVS diodes on both sides of locomotives' electronics (motor side and track side) as well as across transformer outputs and any other accessories using solenoids or motors?
Well, this would be pretty rugged for transient protection. If you have good current protection to go with that ... then it's pretty unlikely you could damage any of the electronics unless being struck by lightning or something.
For fun, I'd like to point out, no matter how clever you think you are, things still go wrong. At AGHR we have TVS's , PSX-ACs, chokes, surge protectors everywhere and a very fine fine tuned layout.
Yet somehow last year the city came and put the transformer on the pole in backwards outside our clubhouse for a few minutes... and we had 750V rms on all our outlets. It was intense, I think we had over 200V on the layout, and the lighting fixtures all blew out. The only thing that survived was GRJ's booster circuit somehow.
Enjoy 16 seconds of video of our train club melting down.
@Adrian! posted:Yet somehow last year the city came and put the transformer on the pole in backwards outside our clubhouse for a few minutes... and we had 750V rms on all our outlets. It was intense, I think we had over 200V on the layout, and the lighting fixtures all blew out. The only thing that survived was GRJ's booster circuit somehow.
Enjoy 16 seconds of video of our train club melting down.
Nothing is fool proof simply because fools are so ingenious! 
@Adrian! posted:...the city came and put the transformer on the pole in backwards outside our clubhouse for a few minutes... and we had 750V rms on all our outlets. It was intense, I think we had over 200V on the layout, and the lighting fixtures all blew out. The only thing that survived was GRJ's booster circuit somehow.
Yea, the best of plans... So did the linemen repair all the electronics on the layout for you? 
@SteveH posted:Yea, the best of plans... So did the linemen repair all the electronics on the layout for you?
Uh the final tally was like 5/5 TIUs, 5/5 WIUs like 10/20 PH180 bricks, 10/20 PSX boards, a legacy base, 5 or 6 locomotives, the LED boards in like 3 passenger cars and the LED lighting in maybe 20-30 accessories.
The city is our sponsor so we’re not allowed to get mad at them. Oh well.
Well, that stinks. I hope you all were able to find the funds to replace all that equipment.
Anyway, thank you Adrian, John, and Brian for your insights on this query. I have a bunch of TVS diodes coming soon and I look forward to opening my locomotives to do some modifications. 
@Adrian! posted:The city is our sponsor so we’re not allowed to get mad at them. Oh well.
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