Or is it the previous-release shell with a sound-equipped frame?

Judging from product photos, the new 40' AAR box appears to be a sterling effort at better, finer detail, fully in line with Bachmann's overall improvement in product quality. But, pray tell, why was the post-1969 medallion used on the UP version? It would have never been correct for the "Automated Rail Way" lettering on brown cars, as the "Automated" slogan was dropped in favor of "We Can Handle It" shortly after "Railroad" disappeared from the medallion. I.e., there were no "Automated" repaints of the now-old 40' cars using the post-1969 logo.

[sigh]

Why do we have this knack for doing such a great job on stuff, and then blow it on big eye-catchers?

Big "thumbs up!" on the 70-tonner. Certainly a logical evolution of the work done on the 44-tonner.

I do need to seriously ask: what is the logic behind the GP7? This is a well-covered prototype in N.

First, my thanks for a great model. I have five from the first run, and am looking forward to more from the announced release to add new numbers to the fleet. A few questions:

• Is it safe to assume that the new release will come with the new couplers? If so, given the coupler pocket changes necessary to accomplish this, will the parts be available to retrofit to the previous run?
• Will the truck frame profile be corrected... hopefully... please? It is the most glaring model fidelity issue in the new design. And if so, can we get retrofits?
• Will the horn casting be corrected? If the intent was to capture the Leslie S5TRRO, then it was a huge miss, emphasis on huge. However, it's easy enough correct in the aftermarket - the trucks are not.
• Will parts be available generally? We've been somewhat frustrated by having to buy whole models just to get pieces for kitbashing and details correction. Plus the nice, fine handrails (THANK YOU!) are... uh... a little fragile. (Oops.)

The biggest issue to me and many others is the truck appearance. It would save a huge amount of work if they were re-profiled for better fidelity to the prototype. The other detail issues are easy enough to correct, including the swiveling pilots, but the trucks are a major effort to re-model.

Thanks!

No, not correct. This model is designed to run on 9-3/4" minimum radius.

FWIW... while the wires are plastic-coated, I found that on mine, the soldering work attaching the wires to the socket which plugs into the tender was... well... not the best. There were also a couple of wires twisted together that were likely touching where the the wires were over-tinned but still a little flexible.

Mike, I suspect that you're looking at the same problem. Check around this connector and make sure that all the wires are straight out of the connector and not kinked together close to where they are soldered to the socket board.

DCC is going to highlight weaknesses like this because of the increased requirements for isolation. Your (and my) locos ran fine under DC because it was likely that the short was across circuits that were jumpered together for DC but isolated for DCC. I would also suspect that both of ours passed QC because they ran fine on the test track but there was no separate QC procedure verifying everything was still good for DCC after it was assembled.

I'm replacing them with a TCS (Train Control Systems) M4. I'm rewiring mine for separate control of the beacon and future provision for controlling the marker lights separately. If I was replacing the stock decoder pin-for-pin, it would be with the TCS M1.

The humming you hear is likely a power dithering mode to help with low-speed control. It's normal with low-end decoder designs.

I've run three different "copies" of the new DDA40X under DCC, and aside from unusually long momentum settings have had no problem as you describe.

That said, this decoder is very basic - too basic - and is the process of being replaced in all of mine.

Yeah, I have my concerns about this, too.

In a fit of incredibly bad timing I bought two "Plus" versions new from hobby shop "old stock" last year... weeks if not days before the new version was announced. And a little too close to MSRP. Both had broken axle gears out of the box, and have not seen daylight since their five minutes on the test track. In other words, $200 worth of "new" models that won't ever be runnable.

I can understand that the warranty was not intended to serve the "modeler" market, but, rather, as a marketing tweak for the general consumer trade. However, since the models I purchased were defective from the get-go and parts are not available, I would expect replacement with the equivalent model since it is available.

I'll wait a couple of days for our concerns to be heard and then call the service department. Hopefully we can expect a better outcome than "sorry... replacement from surplus stock of another model of our choosing" since in all honesty that's not what we signed-up for. "A locomotive is a locomotive" only works for beginners.

I'll add that it seems slightly incongruous that Bachmann has done backflips to make the new Centennial an excellent model which appeals, finally, to the modeler, and then tells that same customer that their modeler concerns - seeking a specific prototype - are going to be ignored when it comes to product support.

Thanks for hearing us out.

...mike

Yes. Also, as I said before, the front headlight and beacon are connected together, and the beacon flash rate is not determined by the DCC decoder.

To do what you're asking is going to require replacing the decoder from the aftermarket and modifications to the circuit board.

Rivet-counting time: I don't know why Bachmann calls it an "MDT", because Plymouth "M" models have four wheels, not six.

It could be an interpretation of a "WDT" (IIRC, Atlas called theirs a "WDT"), but the published photos of prototype WDT's show them with an internal bogie frame. I'm going to hazard a guess that the model is a loose interpretation of either a very-late-model WDT and immediate precursor to the CR-6, or, possibly, an adaptation of a narrow-gauge version, which would have the external bogie frame.

Unfortunately, what you see is what you get. The DCC is standard 8-wire NMRA plug-compatible, with no extra functions for the strobe. The strobe is connected in parallel with the front headlight, with flash pattern determined by circuitry on the main board. You might be able to program a CV to turn off the front headlight (and strobe) while in reverse, but that's a guess since I don't have a chart for the decoder, either.

Anything more complex means a complete rewire and pretty much tossing the board that came with it.

BTW, I figured-out the problem that so many are having with the trucks - the detail itself is pretty good, but the brakes "layer" is not very deep - certainly not deep enough. So the brake shoes and hangers have the appearance of being virtually in the same plane with the sideframes.

Two solutions - paint the brake parts black/grimy (like they are in real life), or cut them out entirely. Makes me wish that I picked-up that pair of loose Overland DD trucks on eBay a couple of weeks ago to modify and use as masters for something a little better in resin.

In the above, replace "Omaha" with "Council Bluffs". Yeah, a rivet-count, but I thought that I should catch it first. 

Anyway, I'm going to back down a little bit about the "speedy" top-end of the DDA40X model on DC. I was testing it last night with a Kato SD40-2 "snoot" that I'm renumbering to be an 8000-class SD40-2H, and the Kato was nearly double the speed of the new Bachmann at any given throttle setting.

The test was a comic moment, fully in view of my wife, who then started to ask all sorts of questions I really didn't want to answer. I normally test speed matching on my test loop by putting each loco on opposite sides of the loop and see who catches-up first. The speed difference was so big that the Kato caught-up to the Centennial so quickly I couldn't kill the throttle fast enough, and WHAM!!!. I had to examine couplers for missing bits. 

The speed problem with the Kato is so bad it's looking like DCC is in my near future whether I like it or not.

Quote from: r0bert on August 26, 2009, 07:52:38 PM
Keep in mind that the DDA40's were geared for 90 mph+ operations pulling express reefers, not yard service.

Uhhhhhhhh... no. Three things to learn here.

First, there was never any location on the pre-merger UP where speeds over 79 were legal. This required a system known as "Automatic Train Stop", which UP didn't use. The 6900's may have been geared for high maximum speeds, but that gearing was primarily to improve operating efficiency in higher speed ranges.

Second, DDA40X's were rarely if ever used on the expedited PFE (reefer) trains of the day. Very little produce originated on UP lines, and the priority trains were typically joint run-through (no power change) operations with SP handling the origination in California. Other railroads were afraid of the DD's and wouldn't let them on the property, and while SP had three DD35's, they would not run them over Donner Pass, and would not let UP run theirs over Donner either. Of special concern was that the 100-foot-long Centennials would scrape the sides of curved tunnels and snowsheds. So the express produce trains of the day typically drew new C-C's.

Third, what they were was the power of choice for expedited intermodal service, usually with an SD40-2H sandwiched between two, but sometimes three of the "Big Jacks" were at the front. Intermodal in the '70s was mostly TOFC since COFC was just starting, and included trains such as the "VAN", a hotshot between Omaha and Los Angeles.

However, the TOFC use wasn't exclusive. While DDA40X's were not "wasted" on drag freights, coal service or slogging the taconite trains, they saw the majority of their service on any UP train that was end-to-end - between Omaha or North Platte and L.A or Portland. UP consistently over-powered their trains during the '60s and '70s, and the 6900's moved those trains along pretty smartly.

They were very, very impressive to experience in operation. My hat's off to Bachmann for taking the trouble to revisit this prototype and produce a worthy model of it that, if not 100% perfect, certainly captures the flavor.