I've some question, Could I connect between LGB and USA train G:Scale track? please advise.
Yes they are interchangable, with one or two small cautions, LGB and USA/Aristo rails have slightly different web widths so the joiners need a little gentle "persuasion" to couple, but once connected they stay together fine. I have a mix on both on my indoor layout.
Couple other tidbits of advice
LGB uses optional plastic spanners to connect the last ties on the track sections, you don't need them but they do a good job to keep the sections together.
USA/Aristo track uses small hex set screws through the joiners to tie the track sections together, they are a pain in the neck to install (use the little hex head screwdriver that comes with the track box) but they are really tied together once installed.
You cannot use USA set screws on LGB track, but the compression between joining the USA and LGB ties them pretty darn well.
BTW USA track and Aristo track are one in the same, they come from the same factory, hence the association.
Have fun with your trains
As Vic said, they work well with each other. The only "problem" I've had is the different rate the two "patina". The LGB patina's faster and more to a color that I like best. After about a year outside the LGB looks like it has been there 10~20 years, the USA looks like recent repairs/replacements. I've taken to using a lighter color balast to enhance the newly repaired look.
Tom Trigg
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