Those streamline cars date back to Penn Line, who left the train business in 1964 and a portion of their tooling and products were purchased by Varney, who produced some of the items just before being sold to become Life-Like.  There are baggage and RPO cars that match the other cars, I have at least one of them here, but it appears they haven't been made in a long time and you may be on your own with regard to painting them to match. 

Better send it in for a warranty replacement.  I had an On30 forney do the same thing - the decoder failed, in fact just about caught fire and if you take the shell off you will probably find one of the chips glowing white-hot when power is applied to the locomotive.  After I removed the decoder and replaced it with dummy plugs, the engine would still only operate in one direction - the failure also damaged the permanent circuit board inside the locomotive.  The HHP-8 may be designed differently or it may be the same components arranged differently -

I actually would not be surprised if it's a while before anything really new is introduced.  No one's announced much new recently and what was most recently announced has had a lot of delays getting here. 

Having both 4-4-0s side by side, I can't see where they share any parts, except headlights and smokestacks (some of which are also shared with the 2-8-0).  Perhaps some internal parts as well (motor, PC boards, the same decoder). 

The On30 loco will be much wider than HO rolling stock and should be very visibly taller when parked next to HO equipment. 

The whole point, however, of On30 was to have O scale narrow gauge that would readily run on inexpensive HO track.  As such, most of the locomotives are very small, although the sizes vary depending on the size of the prototype - some are based on 2' gauge (IF 4-4-0, Forney), some on 3' gauge (2-6-0, 2-8-0, 4-6-0), and one on actual 30-inch gauge (the 2-6-6-2). 

The NRHS chapter here has the sad remains of an 18-inch gauge 0-6-0 and it's incredibly tiny - you could haul the whole thing on the back of a rollback truck in the same space most automobiles will fit.   But it's a real live locomotive from a quarry, not a replica or amusement park ride. 

One can carefully score the cab down the sides of the center panel and remove it, after the handrail across is removed.  I did it with mine before I sold it as too large a loco for my system. 

As for the tender, all I can see is shortening it, perhaps setting the body on the frame of an HO bobber caboose - some 4-wheel tenders did use this sort of suspension arrangement. 

Or just sell it and get the inside frame 4-4-0, which is shorter and will fit easily on a 9" turntable. 

Well, there always is the ubiquitous Atlas 9" turntable.  Which makes a good temporary piece and will turn anything except the 2-6-6-2 (and maybe the big 4-6-0 and 2-8-0s).   I have one on my layout now, for the time being, because where the table wound up is right on a joint between benchwork segments.   

They did, however, come up with a new RS2 and GP7 in HO in that time.  Given how many of those are already on the market, not sure why, but if they're willing to chance that I don't see why more On30 isn't an option. 

They come with different parts installed, but they all come with three choices of headlight and two choices of lead truck.  The problem is at least on the outside frame undecs, the lower tender tank and cast type rear truck only come on the wood cab version, while the steel cab version has the arch bar rear truck and taller tender deck.  To me this doesn't make sense, the steel cab one should have the cast truck and should come with the electric headlight installed, not the oil headlight.  I didn't realize that until I'd bought two of them, though, and I'm not sure I want to mess around buying two more to try to swap out the pieces and get them how I want. 

Woodland Scenics has dry transfers in several lettering styles.  I've used some of the roman numbers on my locomotives.  Anything more than railroad initials will be tedious to apply, though, I would look into having decals made if possible. 

The data is really up to your own preference - it was/is primarily only required on revenue cars that are interchanged between roads.  Not a lot of narrow gauge roads connected to one another to do that.  When the car never leaves the home road, information on brake overhauls and load capacity and so on could just be kept in a written log someplace. 

.. I don't understand why the undec Davenport comes with the headlight and exhaust stack glued in place.  I had to remove the headlight to paint it seperately and broke the pin off the bottom of it.  The light is glued to it's base platform and the base has one pin which is glued into the shell. While I was able to deal with painting the stack with a brush, I didn't want to try to mask the headlight when spray painting the shell, especially to try to paint under it.

I also don't understand what the deal is with the bell - there's one packed with it, the hood has a flat spot where it might go, but it's not opened for it, and the bell is not shown in the instructions at all.  Which itself is fine, but the bell has a square peg and will be tough to file it round to fit the round hole a drill bit will make. 

I had to make a set of doors for the cab, as it has none, but when used in colder climates I would expect they'd have doors and a heater in the cab. 

Also missing in the instructions is that the shell should be removed in two pieces - the cab first, then the main shell, and that the shell kind of snaps in place at the rear, it doesn't just pull off.


Just some thoughts for the next run on these, or if they turn around and try to do a version with sound.

Spins it's wheels?  Something physical must be hanging up to keep it from moving.  A split gear might cause it to run and not turn the axle, but then because the split widens a gap between teeth it should also cause some binding issues.  

A rail bus in trade for the truck is not a bad deal, they generally bring more money on eBay, you could almost take the swap, sell it, buy another railtruck and come out ahead by a few bucks.   Personally I'd like to see a railbus kitbashed where the trailer and bus are combined into one unit with a more realistic appearance. 

Have you seen what a complete one generally goes off for on eBay?  I don't think you can get half the parts through Bachmann, for the average sale price over there.  They have it divided into several major assemblies. 

I wouldn't mind swapping out the arch bar rear trucks on mine with the other style, just fwiw. 

I'd be tempted to send it in and see if they'll just replace it with one from the new run.   Would be well worth the $20 or $35 or whatever the fee is for being out of warranty.

Several of my passenger cars and at least one caboose date back to the first runs, the cars are from one of the sets, I'm running an early MRC Prodigy DCC and while the lights are bright, none of those that are still hooked up, have burned out.  Most have a lot of hours on them.