Northwest Short Line makes a self-contained power truck, the "Stanton" truck.  They come in a variety of wheel base lengths and wheel sizes.  They are a bit pricey, but should last a long time.  Check the on-line catalog.

The coupler trip pin is curved in order to resemble the brake air hose hanging from the end of the car or loco. 

Trying to combine DCC with three-rail AC courts disaster.  It would seem to me that you would need to totally isolate the entire crossing electrically and use a DPDT center-off switch to choose either the AC side or the DCC side. 

Walthers, Megow, Silver Streak, Central Valley, Ambroid, Main Line, and many more made what are now referred to generally as "craftsman kits".  A box car kit would generally consist of pieces of milled wood for the floor and roof, scribed wood sheet for the sides and ends, and various sizes of strip wood for trim, roof walks, etc.  There would usually be a handfull of soft metal castings for end beams, ladders, brake gear, etc.  They might give you some common staples for grab irons.  The good kits came with pre-formed grabs.  Some of the kits came with painted and lettered sides; others, just decals and you had the paint the car body first. The kits came "LTC" - less truck and couplers.  I built a number of them in my day - still have a few stored in some boxes.  With careful work, they could build up quite nicely.   

We have an AR-2 installed on our club's trolley line and it works great.  The end delay is adjustable.  We have it set for about 45 seconds which seems OK for our purposes.

What exactly is happening?  Is it derailing?  Stalling?  Shorting?  Need more data.

You will be better off if you use code 83/code 100 coversion rail joiners for a smooth transition.  Atlas makes them.  Walthers catalog part number 150-551. 

The spacing of division points had more to do with what constituted a "working day" for the road crews.  In the steam days (and early diesel days, too) union agreements generally set 100 miles and/or 16 hours as a working day.  This was sometimes referred to as the "hog law".  100 miles in 16 hours works out to a little more than 6 miles per hour.  This sounds real slow, but the local way freight could kill a couple of hours at each town working the various indutries.  They may run at 30 mph between those towns, but the over-the-road time was slower.  One reason passenger service was such high seniority is that the crews might hit that 100 mile mark in a couple of hours and their "day" was done.  Modern steam didn't really need much at the end of a run besides fuel and water.  An ash dump too, if coal fired.  Unless the crews noted something needed attention, the hostlers could turn an engine around to the ready track in a couple of hours. 

I'll hold up my hand.  All the major motive power is steam, both rod and geared.  There is also a gas-electric car and some small MOW rail critters. 

Yes, understand about household accidents.  In addition to the Alco model, I have the Bachmann versions of Nos. 4 and 6 and the Ten-Wheeler.  I've joined an HO club near our second home and like to have some items to run there.  I also kept the Westwood passenger set, which looks real good behind any of the locos.  Those kits built up very nicely, but were something of a pain to assemble. 

I believe every piece of motive power the Ma and Pa bought (not counting the second-hand power the road began with) has been produced in HO:  The three Richmond 4-4-0's from Bachmann; the modernized No.6 from Bachmann and Alco (brass); the Ten-Wheelers (Bachmann; Olympia/Gem and Olympic Express (brass); the old-time Connies (PFM brass); the 3 modern Connies (PFM and Overland (brass); The two 0-6-0's (Westside (brass); plus the gas-electric (Gem (brass).  Gem also did brass models of a passenger car and caboose.  Westwood made a 2-car craftsman kit to build the arch roof RPO and a coach.  My first brass model was the Olympia/Gem Ten-Wheeler, which was advertised in RMC for $29.95, circa 1963.  At one time I had the complete collection of Ma and Pa brass models, except the Oylmpic Express version of the Ten-Wheeler, which was pretty crudely detailed compared to the Gem version.  Sold traded almost all away when I went into O/On3. Kept the Alco No. 6 which I had spent about 30 hours redetailing to make it correct.   

jonathon:  Really nice work on blending the foreground scenery with the background print.  Keep it up!

If you want more track, you will want to go with Atlas "Snap Track".  It comes in 9 inch straight peices and a variety of curve sizes.  The Bachmann "EZ Track" is raised up with a representation of ballast, and won't directly work with the 1950's era track which just has rail and ties.  Also, make sure any track you buy uses nickle silver rail.

Go here for the tender diagram:  http://www.bachmanntrains.com/home-usa/dwg/dwgs/HO_440_DCC-tender.pdf
It would appear that there are two screws towards the front corners of the tender floor that would help hold the tank down.  That's a good start. 

I have had the same issue with an older K-4 - it was an effort for it to pull even three passenger cars up a similar grade.  It probabaly needs more weight, but I haven't had the time or motivation to open her up and see if there's room for any more.