Detailing, Construction and Paint:




These units would be what I consider to be Marklin's fourth generation F7 tooling, the same tooling used for the 26496 ATSF Super Chief and 39620 Soo Line sets. Some details include:

-Improved nose/window shape
-Marker lights and detailed running numbers
-Cab interior details
-Grab irons on nose and cab
-All metal construction as with previous Marklin F7 units

They feel about the same as any other Marklin F unit. They are attached with a permanent drawbar that allows for a very small gap between units.

As far as the paint is concerned, it is perhaps some of the best quality paint I have ever seen on a Marklin model. The crispness is outstanding, these units exceed those of any previous generation of Marklin F7 (although are probably the same as the Super Chief and Soo Line units which I have not seen in person). Marklin have done an excellent job with the quality of paint and detail on these units. Even the fine Great Northern seal is easily legible:



Regarding the livery, Marlkin has done a pretty good job. Freight units such as these had black trucks instead of silver trucks, as is captured. The only obvious difference between a prototype and the model is the silver side louvers/vents. As far as I can tell, these were almost always the same green as used otherwise on the body. However, most colour photos are from the 60s, and as a result it could be possible there was an earlier phase of this livery that was silver.

Unit 423, which has been restored sometime within the past 15 years, does sport some silver vents:

It also looks like these untis with the simplified green/orange scheme have silver vents, but hard to tell for sure:

As well as this unit with the simplified scheme:


Included in the box (but not pictured) are coupler pockets for NEM couplers and snow plows.

Operation, Sound and Digital Functions:

The locomotive is equipped with a mfx+ sound decoder, allowing for cab operation with CS2/3. There is no locomotive icon, I added one myself.



Digital functions:
-Headlight
-Number board/marker lights
-Diesel running sounds
-Horn
-ABV off
-Squealing brakes off
-Cab Radio
-Coupler sounds
-Letting of air
-Rain joint sounds
-Switching range

Cab control works fine, but I do not use it. I set the locomotive to "standard" operation mode. If you forget and run out of fuel, just reset the decoder from CS2/3 and then change the mode.



Sound:

As with the 37935 ATSF Mikado, the sound in the latest generation decoders is outstanding. The sound was quiet loud, I had to turn it down a bit to match my tastes. Crisp, clear and detailed. The sound is improved from mfx equipped 3rd generation Marklin F7s like B&O 37618 and UP 37629. I think the sounds may all be new recordings, but there is no way to know. The cab radio recording is new from that previously used by Marklin. I wish that Marklin had included one or two more cab radio sequences.



Lighting:
The LED lighting is an improvement from previous generations. The quality and brightness are good. This is the one area in which I think this model could be improved, inclusion of cab lighting as with the 39620 Soo Line F7s, and also with dual headlight bulbs as with the prototype.





Running quality and power:

Both units are powered with DCM motors. Each unit has two powered axles (rear truck) and two traction tires, for combined total of four powered axles and four traction tires. The DCM motors are fairly quiet compared to other DCM motors I own, but they are still noticeable, increasing as expected at higher speeds. As this is a diesel locomotive, the sound does not detract very much. There is a single slider which makes no noticeable noise. The unit is equipped with metal Marklin F7 style couplers the same as those used all the way back to ATSF 3060/4060 on both units. Typically these couplers are very reliable and do not let go

Running otherwise is smooth and perfect, no derailments, wobble, etc. The pulling power is very good due to the weight of the units and the double motor configuration. My quick test reveals no problem pulling 12 four axle 50 foot tin plate cars up and down 2% grades, as well as around R1 curves. I will likely add more load in the future, and will try to remember to include the results. I expect it should be able to pull as much as the other double motor Marklin A-B-B and A-B-A sets issued in the last 20 years.

Conclusion (or quick review):

This is an excellent F7 model from Marklin. It has superb masterclass quality paint, sound and pulling power. Digital control is smooth and operation is reliable. I love this livery, and would absolutely recommend these units. I got these despite my general restriction to only purchase motive power for railroads found in Colorado and Utah: ATSF, D&RGW and UP.

Minor suggested improvements: cab lighting, improved headlight design for the 4th generation tooling (2 internal bulbs like the prototype), and additional radio chatter. The sound is so good I want more! However, none of this would keep me from purchasing this unit.



-Brandon

Updated pulling power test, up and down 2% grades, and done at low speeds (FS 2 through 24):

-16 US 50 foot tin plate 4 axle boxcars
-8 US tin plate 4 axle tankers
-3 US plastic 4 axle gondolas
-2 US plastic 4 axle flatbeds
-1 US tin plate 4 axle caboose caboose (courtesy of ATSF)

Total cars: 30
Total axles: 120

Passed with flying colours. This is the utter limit test for me, running trains this long is not a regular business. CS2 reporting 0.175-0.2 amps consumed under this load for 39621 w/headlight, running boards and operating sounds. I did, however, forgot to take the idle 37622 ATSF F7 A-B off the layout.



-Brandon

If Marklin were to creep over in to era IV US motive power, there are almost endless rainbow era combinations as railroads consolidated and combined operations. I wonder if such units would be popular?

If nothing else you could mix the stock :)



-Brandon

If proof is needed to run this A-A configuration along with Marklin friendly rainbow boxcars: