I'll have to look later, but that might be the one the Tweetsie pawned off on the EBT back when both roads had interlocking directorets   As far as is known, the unit never turned a wheel in regular service on the Broad Top, and they acquired the M-1 instead.  It looked a bit like a cable car body with a hood out front.

Mostly this is a matter of how much area you want to cover with paint.  If you have sizeable expanses of plaster, go get a gallon and get it tinted at the paint store to the color chip you like.  If there is a question, go lighter rather than darker.  For more detailed areas, tubes of artist's acrylics are useful (say you want to model a freshly plowed garden plot that has good, dark topsoil.  Burnt Umber straight from the tube might work.  If you have a railroad cut through sedimentary rock, you might want to paint in some different colored layers to represent the different eras the sediments were laid down.   Stick mostly to "earth" colors--Burnt umber, raw umber, yellow ochre, burnt sienna.  Almost nothing in nature is dead black, except fresh-mined coal.  Any coal or shale seams that are exposed to the elements will fade to some kind of grey-brown from weathering.  Under most model railroad lighting conditions, the coloring should be on the subtle side, or it may look too dark or too garish.

Another potential option that some folks have used is to get a "dry" nitrogen tank from your local compressed gases dealer.  The initial cost will probably be in the range of what a good compressor and tank might cost, but then you only need to turn in the tank for a fresh one and the cost of filling.  The advanges are that dry nitrogen will not react with any of the paints, there is no compressor noise, and a tank will last the typical model RR painter a LONG time.  Yes, you will still need a regulator and should install a moisture trap just for back-up. 

How tight a curve a loco will handle is a function of how many compromises to scale that you can live with.  The Large Scale models took some liberties with the Tweetsie locos to handle those sharp curves.  Could it be done for On30?  Probably--they've gotten the Ma & Pa Ten-Wheeler to handle those curves, and the mechanisim isn't much smaller than a narrow gauge O scale model would be. 

Mr. Bach-man- How come the system keeps "losing" my password?  I've had to re-install it every day now for the past 3 days.  What's the deal?

The BRB&L locos were for the most part 2-4-4T Bogies.  They looked somewhat like the Bachmann inside-frame Forneys, but maybe about a third bigger, and with drivers about 48" diameter. 

Your best bet is to stay in the Cumberland/Frostburg area.  There is a big variety of motels at the LaVale exit off I-68 (just west of Cumberland) and a couple at the next exit west (Frostburg).  You are within about 30 minutes of Sand Patch in either case.  There is nothing of consequence in the way of accommodations along the B&O route between Hyndman and Meyersdale.

In most cases, the movie folk create ficticious names to avoid potential copyright issues and defamation suits.  Exceptions would be movies ABOUT the railroads--"Union Pacific"; "Denver and Rio Grande" come to mind.  I suspect that Sierra RR No. 3 has had more road names painted on her tender than Carter had pills.  The little 4-6-0 is perhaps best remembered for her supporting role in the "Petticoat Junction" TV series.

I second most of the comments re:  brand of airbrush.  Most any name brand is a good investment.  Many people get along very well with a single-action brush.  A dual-action brush is considered the "gold standard", but a lot of folks never quite get used to them.  Something else you need to be aware of is that there are different tips for different paints.  I went to a Badger clinic in Philly last year, and they were emphatic that you need to specify the tip for the paint you'll be using.  A tip for solvent-based paints is different than one intended for water-base acrylics.  They also noted that you need to thin the acrylic paints.  The paint should be the consistency of milk for proper spraying.  Most solvent-based model paints are OK out of the bottle, though some thinning never hurt. 

Full disclosure:  I used a Wold dual action Master M for decades.  Works great for solvents; clogs with acrylics.  I bought a new Badger to use with the new paints, and because Wold went out of business and I can't get parts any more.

OK, we're past 4/1, and this is no joke.  The "Big Joe" story is a fabrication with some basis in fact.  The Russians did in fact decide to built the world's largest rigid frame locomotive, and proceeded to built a 4-14-4.  It apparently made one long test run, and it is only some exaggeration to say that it spend as much time on the ties as on the rails.  "Urban legend" says that the locos designers got sent to the gulag, and the engine quickly scrapped.

The critical issue is the space between the driver flanges.  If the gap is greater than the 7 scale inches, you might get away with it.  7 scale inches is about 3/32", if that helps any.  Couple of things.  You might use slightly smaller drivers, like 76", and/or use blind drivers on the two center axles.  May not be prototype, but it will help in getting the loco around sharper curves.

FWIW, the PRR apparently contemplated a 4-8-4, but built the T-1's instead.  They also used a few ex-N&W Y-3's during WWII, so maybe that's where all this started.  I tend towards the April 1st answer, though.

The Spectrum 4-4-0 will (barely) pass around an 18" curve.  It appears that the pilot truck might drag a bit on the back of the cylinders, but it will do it.  However, I'd probably stick with 22" curves for better reliability.  Bachmann does provide you with jumpers that you place in the DCC plug in place of the decoder for DC operation.  No sound, though I would expect someone to offer a sound module for this model sometime soon.  I think you can wedge an MDC unit in the tender.

Hamish: My appologies.  Pulled the trigger before aiming.  Yes, most all of the BRB&L locos were of the Bogie design, though built by 3 different builders.  It isn't readily apparent from the pics, but is definitly noted as such in the chapter on Locos in the book.  Amazingly, one of them lasted (in stationary steam service) till the end of electric service in 1940.  For those unfamiliar, the Boston, Revere Beach and Lynn was a 3-foot gauge pike built along the beaches north of Boston with ferry connections into the Hub City.  The road began with steam in the 1870's, and converted to electricity in 1928.  Bad timing, as the conversion was expensive, and the Depression hit almost immediatly, so the road quit in 1940.

As near as I can tell, virtually all of the Revere Beach locos were Forneys, not Bogies.  As noted, the difference is that the drivers and frame rotated under the boiler with Bogies, while the Forneys were rigid.  I suspect one of the downfalls of the Mason Bogies (and Mason also built Forneys) was maintaining the flexible steam connections between the boiler and cylinders.  IIRC, there is a Bogie at the big museum (Greenfield's??) near Detroit.