Bachmann Spectrum #89525 is an HO heavyweight 4 car passenger set in Pullman green.  What is the minimum radius for E-Z track that these cars could use in a reasonable operation?  Thanks, whm2255.

22"radius is recommended

I have the NYC version of these. And the recommended is 22 degrees. My layout is 22 degrees main line and the rest is in 18 degrees.  As I am typing this I am running 4 of them  "reliability" test on them as I just changed from the Bachmann standard couplers to the Kadee #148's.  After 60 minutes they are still running just fine weaving in and out of the curves and switches (DCC switch styles 44130,44131,44137 and 44138).  I could not do this on the standard couplers.

I have had a few problems with the the spectrum passenger cars initially and after a switching the couplers and a few other small adjustments (i.e tightening or loosening screws and such) they run great. 
Next I am going to figure out how tho stop the lights inside from flickering when they over the switches.  I know the answer is on here somewhere.

If they run on 22" radius then that answers that question.  About the lights:  Your question takes me back to my American Flyer days when lights always flickered.  hehehe  You have a couple of choices, the easiest thing might be to wire the lights of a couple of cars together, effectively giving you twice the number of wheels to pick up power.  Another option might be to use a capacitor in the lighting circuit to eliminate sags and surges in power.  Perhaps one of our electronic gurus could suggest what size would be appropriate.  Lastly, you could disconnect the lights from the trucks and run them off batteries with a small switch to turn them off and on.

....anybody know if the stndrd unmarked Pullman green and the Santa Fe are the same?   They look similar in photos.

taku
They look the same don't they. I bought mine on eBay from the seller "thefavoritespot"
You could check with him.  But he does take pictures I think of each type of passenger car he has. Hope that helps.
Robert