Review

Athearn's Genesis line has just gotten richer with the addition of the SD70MAC. The big purchaser of the Big Mac has been the Burlington Northern Santa Fe which is reproduced in the Phase VIIb wearing Premium Heritage paint, the Phase III in BN Executive, and BNSF Executive Warbonnet. Conrail Phase VII models join with CSX's YN2 "Bright Future" paint, YN3, and Conrail/ CSX patch jobs. Each paint scheme offers two or three roadnumbers which will change with each new batch to be released. The Prototype No. 9897 Back in 1993, Burlington Northern made an unprecedented move: they plunked down $675,000,000 for 350 locomotives of a type which hadn't even been made yet!

They had helped to test and perfect the SD60MAC, but there were only four of those ever built. When it came time to buy, they chose the AC version of the year-old SD70M. They own something around 785 of them and, no, you can't have one of theirs. Hauling Powder River coal from Wyoming down to power plants in Texas is a continuous, year round business with special needs. It isn't just the 4,000 horse 16-7106 prime mover or the HTCR radial, self steering trucks. These locomotives face a challenge when it comes time to load and unload, since over a hundred cars are pulled continuously at about 3 mph under the loading tipple.

The train gradually gets heavier, and the load plus slow speed was a torture to the older DC-traction locos. Their traction motors would overheat unless a whole bunch of them were put on the point. AC traction motors just don't get that hot and can crawl with a load all day long. Number 9897 carries General Motors Locomotive Group builder's number 976814-33, one of 78 members of her class which began with roadnumber 9865 in May 1998 and went through 9942 in December 1998. Our unit was built in September of that year. By the time of her construction, the merger of Burlington Northern and ATSF was old news, so it arrived wearing Heritage II warpaint. Like most of the BNSF units, she weighs in at 412,000 pounds and can exert a starting tractive effort of 175,500 pounds with 137,000 pound continuous. She is 74 feet, 7 inches long, 10 feet, 3 inches wide, and 15 feet, 9.5 inches high. She runs on 42-inch wheels, a gear ratio of 85:16, and carries up to 5,000 gallons of fuel. The most recently built of BNSF's SD70MACs were constructed in the year 2000.

More importantly is this thought: have the last of the SD70MACs been built? That's an open question as it has been four years since BNSF has purchased any. Alaska RR bought 8 this year, CSX and TFM haven't bought any since 2000, though CSX has 55 due by the end of this year, and the other major railroads haven't purchased the SD70MAC at all. General Motors is currently testing a newer version called the SD70ACe. SD stands for Special Duty (meaning 6-wheel trucks), the 70 is for the 710 V-16 engine, and the AC is for AC-traction. The M in MAC is the designator of the wide-cab design, and that would be changing to a different cab structure.

The ACe will use the "Karl Malden-nosed" cab applied on the SD90MAC-11 but with something more like the old AAR control stand - removing the letter M - and the unit will also have the same flared radiators as used on the SD90MACs. The small "e" signifies an enhanced performance on emissions standards, a big issue these days. General Motors is working very hard to make AC traction a standard, in part by making it available at less of a premium price. For now, you could probably purchase some new MACS if you really wanted them, but once the 4,300 hp Aces have proved themselves, they will likely become the future. When that happens in the next year or so, expect GM to drop the SD70MAC from its catalog. Still the SD70MAC is where General Motors began its full production of AC traction, and the current fleet is expected to be around another twenty years, at least.

Athearn's Genesis SD70MAC

Fortunately, this same model has recently appeared in Athearn's catalog of Genesis locomotives, where it will remain at least as long. Model No. 9897 might not last long, however. Athearn builds in batches and each batch will be constructed with new roadnumbers, so you can flesh out your fleet with new numbers from time to time. Producing the MAC version was more than just a new paint job on the old SD70M; the MAC is a couple of feet longer and exhibits some noticeable differences from the SD70M, if you know where to look. The most obvious are the four AC inverter vents in the hood section, two on each side, one under the inertial air intake toward the front and another under the second radiator intake in the rear. This shows the extent of modern model railroading's commitment to accuracy; the small difference in length and the additional grilles might have been ignored in the past. Athearn has stepped up from the SD70M and brought the same level of quality and performance while adding a couple of new twists.

The beautiful paintwork is not new; the Genesis line gets nothing but the best, as can be seen here. Lettering features razor sharp edges. The distinctive Heritage II scheme isn't easy to do well, whether on the prototype or an HO model, but Athearn has nailed it. Truck detail on the HTCR-11 side frames is just fine, thank you. A few issues drew my attention. The nose door looks a bit thick, though I can't give you precise measurements to be sure. Proto photos show that the inverters take in enough dirty air to darken the louvers of the vents; this can be simulated with some black chalk. If you just itch to do some real model making, this product lets you install your own windshield wipers

I ran around with the dial calipers, a ruler, and a magnifier, comparing the locomotive to a variety of photos and data sources, finding no major discrepancies. The antenna shroud on the roof is the modern way to collect GPS, radio, and other antennae under one weather cover. The dynamic brake fan grill is metal and the blades of the fan can be seen beneath. The three radiator fans are the appropriate "Q' design, done in plastic under plastic grilles. The horns are actually brass castings, painted appropriately and located just ahead of the radiator section. Just ahead of that are the four engine compart roof hatches, each an X-panel done very nicely. Hood door detail is correct and the knucklebusters look as though they might actually work!

Lift rings are actually open and all of the rungs and grabs are separately applied, most made of metal. Despite having to install the windshield wipers, the back window wipers are installed from the factory, as are the sunshades and the other details. The later SD70MAC might have been called an SD70IAC, because the demarcation line around the nose indicates that it is an Isolated "Whisper" cab design. This was a change to the SD70MAC which started appearing with road number 9572 back in March 1995.1 did notice that there are no cutbars or MU cable around the nose of the model, neither end has MU hoses, and there are no hose ports in the snowplow, though there is a raised area indicating where it would be. There is still some aftermarket detailing to be done.

I especially liked the see-through inertial braking grille with a molded piece inside giving the silhouetted shape of the cooling fan. I could also see the wires headed off to the nose, and I made a promise to myself that I'd see if I could dress see those wires so they didn't show when I installed a decoder.

Operation

Athearn's formidable "Hex Drive" is under the hood, and it runs very smoothly. This model is a little over 18 ounces and can exert 4 or so ounces of pull. The motor is a five-pole, skew-wound unit with twin brass flywheels to keep it all smooth. From about 5 volts on, there is noticeable motor and gear noise, but not enough to be objectionable.

I built a string of 50- and 60-foot freight cars, mostly boxcars, and found 9897 could pull 35 to 40 of them on the straight and level. When I moved the action to Track I with its 18-inch radius curves, the train length dwindled to around 25 cars whenever the train was wrapped around the curves at both ends. This is to be expected, as curves greatly increase rolling resistance.

DC test results were respectable. Low, mid, and high speeds were about right for the model, though those who load coal trains might get that string of cars to temper the unit down to a mile or two per hour, scale. Headlights and ditch lights are directional. The native couplers are Kadee compatible plastic knuckles which came from the factory at the proper height.

DCC

Remove the couplers and carefully pull up on the end sill of either end to pull off the shell. Unlike earlier models which shed parts when you did this, the SD70MAC stayed nicely together. Inside is the famous QuickPlug board, first made famous in the Ready-To-Roll line and now migrated to this project. I wiggled out the plug and installed a Digitrax DH163D decoder. This is, after all, a Genesis and it deserves a top-of-theline decoder.

Of course, our first act upon decoder installation was a trip to the program track where I programmed the address to 9897, the loco's roadnumber. Well, that was easy. I pushed on the shell and took it for a run. Uh oh, suddenly the loco was very noisy. I knew it wasn't the decoder and the sound was of something being pressed against the running gear.

Inside, I found that the black wires headed back to the rear headlight had gotten down the side and were rubbing on the rear flywheel. I coaxed them into staying on top of the frame and the unit was back to running very quietly. I also managed to coax the wiring to be less noticeable through the dynamic brake grille.

As often happens, I got better low-end results using DCC. This is in large part due to the higher AC voltage up through the wheels. Very low DC voltage is prone to contact problems that the 15-16 volts AC tends to improve. As a result, the locomotive started on speed step 1 and ran at just one scale mile per hour. Put that on your coal train!

A rooflme view reveals another source of detail, from the number boards in front to the sand tiller in back. The nose door does look a bit thick, but not at all objectionable.

I noticed the headlight worked, fore and aft, but the ditch lights didn't. I had a funny little feeling about that and started poking function keys. Sure enough, when I poked [1], the ditch lights came on! I could turn them on an off, regardless of headlight status or loco direction. Well, yes, I did poke [2] to see if they flashed, but they didn't. Still, separately

Summary

The Genesis product line has been the vanguard of quality for Athearn, and this model reinforces that position. While 1 have often accused the Ready-To-Roll line of borrowing from that quality, this time Genesis snagged the QuickPlug from the lower-priced line and has added even more value. The addition of controllable ditch lights in a consumer priced production locomotive is a first. Can flashing ditchlights and sound be far away? Stay tuned here.