Thanks for the advice on wheelbase & quality of engine.  I looked up the Mikado on Wikipedia & learned that it was very popular & used up to the end of steam.
  I muffed a chance to buy the Blueline GN Heavy Mikado from an eBay store last night for $150 with free shipping.  Pacific Northern, thanks for the tip:  I just bought one from MBKlein for $150 + $10 shipping.  I have gotten good buys from them several times in the past.  Once, they sent the wrong locomotive (DC, instead of DCC), signed off by 2 inspectors, so I hope they get this one correct (after the boss chewed their butts).  I'll probably just test it & then have to put it away for Christmas.
  I did read the report on DCC decoder problems, but I think I'll just run it as the one DC loco from my E-Z Command.

GN.2-6-8-0.
  That Blueline 2-8-2 Mikado Great Northern is a handsome locomotive!  With DC sound & DCC ready, it compares in price with IHC's 2-10-2 DCC-ready Great Northern.  Counting wheels, I'm guessing that it is more suited to sharper curves than the 2-10-2.  I couldn't find a Bachmann 2-10-2 Great Northern.

 Thanks, GN2-6-8-0!  I'll check that loco out!  I might prefer DC with sound to DCC without, as long as I have one DC address on my E-Z Command.
Thanks, Grumpy.  I wouldn't be as fussy as purists about how it looked, if it managed the curves.

 Thanks everyone, for your advice & expertise.  Thanks for the review, Pacific Northern.  I was wondering whether or not to bid on a Spectrum 2-10-2 DCC DM&IR on eBay.  I have 2 ovals, the inner with 18"r & the outer with 22"r.
  I'm interested in the era of the 1930s & '40s.  Since steam locos with DCC cost more than diesels, I am looking carefully at prices.  I'd prefer a Great Northern, something that would have hauled freight or 100-200 iron ore cars, but models of certain railways seem to be more available & cheaper at the moment.

 I don't have any steam locos.  What's the sharpest curve the 2-10-2 will run?

 Whenever one of my favorite movie stars dies, I feel as if I've lost a friend, because I've spent many enjoyable hours with the actor.  I feel older, too. Newman was also a great humanitarian, donating $200,000,000 to charities through his Newman's Own business.
  Being something of a misfit & nonconformist myself, "Cool Hand Luke" appeals to me a lot; it is also beautifully done.  Newman should have won an Oscar for it.  That he got one for "The Color of Money" was another case of "better late than never" for Hollywood.  Tonight, we watched "Hombre" in memorial.

 I don't think it is safe to bank online.  I never wanted a debit card, because I thought it was a direct line to empty my bank account.  A credit card protects my bank account because they pay the seller & I pay the credit card company.  If I have a dispute with a seller, my credit card company helps.  I think of PayPal as a protection from giving my credit card number to every Tom, Dick & Harry on eBay, & I have PayPal-credit card company-me between my bank account & sellers who are not well-known, reputable companies.
  So far, during a 1 1/2 years of use, I've had no problem with PayPal.  I once had a late payment on the credit card, resulting in interest & a late payment fee.  The bill was either didn't reach us, or we misplaced it.  After what I've read here, I'll be checking the date due on our credit card statements from now on. 

Charles,
Thanks for the ideas.  I didn't know that speed could be adjusted in the decorder.  I was disappointed that, unlike the E-Z Command Control, the booster doesn't have a wire that plugs into the E-Z Loc terminal rerailer.  I was concerned about just wedging the wires under the rerailer's terminals, but the 18 volt setting made a big difference in restoring the performance of my trains.
 I'll pretend that my F7 normally pulls passenger cars.  I've seen photos of GN mixing freight & passenger cars or using the F7 or predecessor to pull freight.
 I just heard the horn of the Union Pacific north of town at 12:43 a.m..  I hadn't heard it for almost a week after hearing it several times a day & night.

Yampa Bob,
That sounds like a big surprise package.  I expected that you would have body-mounted, good knuckle couplers.
  Since we have Union Pacific here in Western Wisconsin, I will acquire a UP DCC freight locomotive, which lets me collect some UP cars, too.

Yampa Bob,
   If I recall correctly, you began this hobby 2 years ago.  You must have collected cars pretty fast, as I seem to be doing.
I'm also trying to find what other railroad's cars GN used in Minnesota during the '50s & '60s.  I remember seeing SOO Line & Burlington Northern, so I added one of each to my freight train.  I'm curious how cars from other railways got onto GN trains.

 I just unscrewed the piece blocking the 18 volt side of the switch & turned it to 18 volts.  Now, my trains run at about the same speed as with E-Z Command Control's 1 amp alone!  I guess I'll quit while I'm even & trust that, if I add a third loco or add sound to my SD-45, the booster will then help.  Thanks, again, Yampa Bob & Jim.

Yampa Bob,
  Thanks for trying to help.  I bought the booster under the same impression as you, that 3 locos would barely move at 1 amp.

Jim,
Thanks for the information.  I was hoping to hear from someone who uses E-Z Command Control & the E-Z Command 5 Amp booster.  I will try the 18 Volt connection.  My Spectrum S-45 I bought new about 2 months ago.  My Intermountain F7A-B I bought new less than a month ago.
  I just don't see why the booster should slow down locomotives that were already scaled down at the factory to run at about half the speed of my train set locomotive.  If I wanted to slow them more, I could run a third locomotive at the same time, add sound to my SD-45, or simply turn down the throttle.
  I e-mailed Bachmann service last night but haven't received a reply yet.
  Last night, I disconnected the booster, because I prefer how my locomotives run without it.

 I see Minneapolis & St. Louis boxcars for sale, but I didn't notice that line in your list.

Jim,

  I clocked my Spectrum SD-45's speed at 85 HO mph & my Intermountain F7A DCC with sound at 69, both at full throttle with the E-Z Command Control's 1 amp.  Adding the F7B did not increase the speed of my passenger train.  Those speeds seem scaled down sufficiently to me.  I just thought that the passenger train was supposed to run faster than the freight when both were pulling about the same length train.
  With the 5 amp power booster, my SD-45 runs at a top speed of 61.8 HO mph, & my F7A-B runs at a top speed of 53.8 HO mph.
  I think that $140 to make my trains slower is a waste of money.
Yampa Bob,
  I used the 14 volt because it is designated for N, HO, & n30; the 18 volt is designated for LS & G.  I wonder if trying the 18 volt would be safe for the trains. 
 

 I just connected a new EZ Command 5 Amp Power Booster to my EZ Command Control.  My Spectrum DCC SD45 & my Intermountain DCC with sound F7A & B run slower with the power booster connected than they do with EZ Command Control 1 amp power!  The booster's green light turns on, & the power to the locomotives shuts off when I turn the booster's switch to Off. I pushed the two wires that connect to the track under the terminals on my EZ Lock terminal rerailer track.  I have the Command Control plugged into an electrical outlet & connected to the booster.  I have the booster's power plugged into an electrical outlet.
  So far, this looks like a big, expensive waste of money that I will have to return.

 I haven't seen in the list Duluth, Missabe & Iron Range, from my neck of the woods.  Also, I see Minneapolis & St. Louis model boxcars.