Model Railroading > Query about what's "under the bonnet"

The manufacturers I name in this post are examples nothing more. I could replace one name with another name and ask the same question time and again (and you'd all get bored). My question is about the sameness or differences within one brand, not about a specific brand or across brands.

I look at various models and I see different body styles and paint schemes. Then I look at the trucks and I begin to wonder how much the HO model makers re-use what goes under the bonnet and on the trucks. The actual design of the bits of truck we see when the loco is on the tracks is slightly different but the wheels, gears, motors etc. how different are they?

Obviously Bowser will be different to Atlas which will be different to Athearn and maybe even Athearn Genesis etc (at least I assume they will but given they all come from China maybe not). It's also the case that as time progresses so various tweaks (improvements?) will happen.

I ask because of DCC consisting and speed tables. My simplistic brain suggests to me that if I buy (as an example) 2 Genesis SD70ACe from the same production run they should run much the same (and experience with the 2 I have suggests that is true). But if I were to add a different 6 axle Genesis loco from the same(ish) production date is it likely to have much the same innards as the SD70ACe? Or am I going to find it necessary to adjust speed tables?

I find if I use the same brand decoder in a locomotive (sound or non-sound) I have no problems getting them to run together. For whatever reason I seem to have acquired more Soundtraxx stuff than others.
One example is a Walthers f7 b unit with a Soundtraxx NON-sound decoder runs perfectly with any or all of my Genesis or older Proto geep 9s. I have a Genesis f45 and a RTR geep 35 both with older Lok (3.5) decoders and I can't get them to run with anything, not even each other (although a year or so ago they ran sweet together). They both seemed to change their CVs while they were in the box on the way home from the club. I also have a cool Proto GP-30 with a Digitrax decoder that hates every other engine I have. I am NOT saying that one brand is better than the other, but for Christmas I'm getting myself a couple of Soundtraxx decoders for those three EMDs and tossing those old Loks/Digitrax.
I know that there is a lot of concern about motors and gear ratios, but, I'm finding that the decoder by the same manufacture is more important than who made the motor. I can run Athearn RTR with Genesis and even that funky Proto SD-45 will run happy together as long as they have a Soundrtaxx decoder.
Please, all of you, keep in mind that the above statements are from a guy that hates electronics and and tends to seek out the simplest solution to a problem. My hobby is building models, the electronic part is just a necessity if I ever want them to move.

Respectfully submitted,

Tom Bacarella

BTW, I'm not saying that everybody should buy Soundraxx stuff. I'm just saying that in my experience standardizing has mostly solved my problems.

I found it interesting that when I had a problem with a couple of Proto 2000 diesels the solution was to buy Athearn axle gears and replace the cracked ones in the trucks. The axle gear design and how the wheels are pressed in is exactly like the Athearn design. Did Proto 2000 pay a royalty to copy Athearns design or did they just copy it after the patent was up? It's obvious that it is an exact copy of the Athearn design but they didn't copy the same material Athearn used. If anything else Athearn is making money on after market parts. By the design being the same it should help speed matching the loco's.

bn4180 I am with you all the way! Could not have said it better myself, I still have my MRC DC power packs and control switches from the 90's. One really bad day and I might go back!!!

Aside from early Proto2000 models cloning Athearn drives to a high degree to where parts are interchangeable, and some Atlas locomotives using Kato drives, you see very little sharing of drive components among manufactures.

Ted Curphey
Ontario, OR

The idea that the same decoder could make dissimilar locomotives run the same had never occurred to me. I think I had always assumed it was the basic electric bits that caused them to run the same.

Thinking about it begins to make sense. I have to admit that, right now, I'm still a little wary of the idea. I suspect that a 10 year old DCC ready loco and a brand new dcc fitted loco will have some differences even with identical decoders but maybe i;m wrong.

I can feel some tests coming on (but not immediately - Christmas!).

Thank you.