The S Scale Journal
Lionel’s SD-70ACe S Scale Diesel
photos by Gary Schrader
Last year, Lionel released its first brand-new American Flyer diesel – the GE U33C (sscale.org/579/volume-1-no-6-lionel-u33c). This year, Lionel’s American Flyer (AF) line has produced another modern diesel — the SD-70ACe. As with the U33C, Lionel’s SD-70 is convertible to S scale operation without too much difficulty. It’s definitely worth a look-see to evaluate its possibilities. The prototype sample model loco shown in the accompanying photos and video has AF wheels and was run on my S scale trackage, but not through any turnouts. A video clip of that operation is embedded above.
The SD-70 offers some significant improvements over last year’s U33C. Two major new features are the addition of DCC compatibility and an ingenious semi-swinging pilot. DCC compatibility is clearly an effort to appeal to the scale modeling market segment and is much appreciated.
The new semi-swinging pilot will satisfy serious modelers who disliked the traditional AF diesel design of having couplers and pilots rigidly affixed to trucks. With that older approach, the pilot, coupler and truck moved as one solid assembly and appeared unrealistic on curves. The new semi-swinging pilot is not rigidly attached to the trucks or couplers. Instead, it can independently move sideways only as needed. Thus, trucks can swivel on curves while the front pilot and front coupler do not need to move at all. This is a big improvement in prototypical appearance. Figs. 1 and 2 show the difference between the two locomotives.
The rear pilot and rear coupler, being coupled to a long freight train, will experience some sideways movement depending on the sharpness of the curve. For a gradual curve, as used by most scale modelers, only the coupler needs to swing sideways while the pilot remains in the straight position. On sharp curves, both the coupler AND the pilot can swing sideways to accommodate the radius of typical AF trackage. This magical feat is accomplished with loose springing of the coupler and stiffer springing of the semi-swinging pilot. It works!
For the fastidious among us, there are two pre-drilled holes in both the pilot and the frame to enable screwing the pilot to the frame to absolutely prevent any movement of the pilot at all. Fig. 1 shows a comparison of pilot swing between last year’s U33 and this year’s SD-70. The improvement is obvious. Again, this design concept is aimed at the scale side of S and is much appreciated.
Other features, now becoming typical for Lionel, are the inclusion of brackets for Kadee S couplers and, for some paint schemes, scale wheels. Some cataloged SD-70 engines have an alternate product number for the scale-wheeled version, whereas other paint schemes will not. As of this writing, it appears that the UP Heritage Series SD-70s all have alternate product numbers for scale wheels. The NS Heritage Series does NOT have alternate product numbers for scale wheels. Thus, the availability of scale wheels for the NS Heritage Series paint schemes is unknown. However, Lionel’s Customer Service tells us that, in the near future, scale replacement wheels will be available for all SD-70 locomotives.
Let me add that the photos speak for themselves (Figs. 3, 4, and 5). The body casting is beautiful. The SD-70 comes with smoke and sound, headlights, ditch lights, cab light, and backup light. Two motors are inside – one on each truck. The die-cast metal sideframes (Fig. 6) are very three-dimensional. The SD-70 runs very well at slow speeds when DCC momentum is added. I did not operate this engine on Legacy, AC or DC, and so cannot comment about operation in those power modes. The loco weighs in at two pounds five ounces, so should pull well. The AF version comes with rubber traction tires and remote-controlled couplers when using Legacy. Individual metal fan blades can easily be seen. All in all, this loco should meet with satisfaction from most S scale modelers. Purists, as usual, can add more details to personalize their locos as desired.
I would suggest careful review of Lionel catalogs and the Charles Ro product listings to determine all the various paint schemes that will be available. It is my understanding that most all of the NS Heritage Series paint schemes will be produced. Scenery Unlimited has some nice color photos on their web site. Locos with alternate product numbers for scale wheels should arrive with factory-installed scale wheels. Locos without alternate product numbers will have scale wheels available for separate purchase in the near future, according to authoritative sources at Lionel.