This review is
from O Gauge Railroading, June 2001. Reprinted with
permission of Myron J. Biggar Group.
Atlas O GM EMD
Scale GM EMD SD-35
low or high nose freight and SDP-35 passenger diesel
2-rail or 3-rail
operation; O36 minimum diameter curve for 3-rail. Molded
plastic body with diecast metal frame, fuel tank, pilots,
and coil-operated couplers. Dual can motors with flywheels,
12-wheel drive with eight traction tires. Includes
TrainMaster Command with RailSounds 4.0 electronics.
Low-nose SD-35 colors:
Conrail, Jersey Central, Pennsylvania, Chessie
(B&)), Western Maryland, Southern Pacific. High-nose
SD-35 colors: Norfolk & Western, Southern. SDP-35 colors:
Seaboard, Union Pacific. Undecorated engines
available in all versions. Length, 16’ coupler-to-coupler;
weight 6 lbs. 8 oz. Manufacturer’s suggested retail price: 2-rail $349.95; 3-4ail, $399.95. Assembled in China for
Atlas O LLC, 603 Sweetland Ave., Hillside NJ 07205; phone
908/687-9590, fax 908/687-6282; web address www.atlasO.com.
When I read or hear of a
new product from Atlas O, accurate scale models with superb detail
are the first things that come to mind. Although I’m not what
one would call an O scale railroader, I really enjoy fine detail
in 3-rail trains and I’m especially partial to large road
diesels – similar to those I see on nearby Union Pacific and
BNSF tracks. So based on my experience with prior Atlas O
products, I had a definite level of expectation for their new
models of the General Motors Electro-Motive Division SD-35 series
of freight and passenger diesel locomotives.
Atlas O submitted two
engines for this review: a
high-nose Norfolk & Western SD-35 and a Union Pacific SDP-35.
Actually, high-nose for the N&W engine could be
considered a misnomer, since the N&W frequently ran their
diesel locomotives long-hood-forward, as attested by the two crew
figure in the cab – they face the long hood. Although the
aesthetics, or should I say the lack of them, of solid black
diesels don’t normally do much for me, the N&W SD-35 is more
than an exception; it’s an unusually handsome model that appears
much more massive than it really is.
As to Uncle Pet’s
(UP’s) Armour Yellow and Dove Gray, this is a highly favored
color scheme and much studied railroad, not only in the editorial
train room but also in my library and at trackside.
The years 1964 through
1966 saw production of the 2500-horsepower SD-35 freight diesel
and the SDP-35 passenger unit at GM’s Electro-Motive Division.
Initially ordered by the Atlantic Coast Line, the SD-35 was a
six-wheel truck variation of the GP-35 with four-wheel trucks; the
six wheels enabled the SD-35 to operate on lighter rails than were
required to support the weight of the GP-35
The EMD 35-series engines
were considered early second-generation diesel locomotives and as
such introduced the angular cab roof, a design style that
continues with today’s hi-tech and high-horsepower
third-generation diesels. GM’s venerable two-stroke turbocharged
16-cylinder 567 diesel was the SD/SDP-35’s prime mover; 567 is
the cubic-inch displacement of one cylinder. With an overall
length of almost 57’ between the pilot beams the SD-35 was the
stubby fore-runner of EMD’s best-selling workhorses, the
16-cylider 3000-horsepower-plus SD-40 series.
Another southeastern road,
the Seaboard, placed the initial order for a passenger train
version, the SDP-35, equipped with a steam boiler for heating the
passenger cars. This boiler was mounted at the back of the long
hood, behind the area containing the cooling radiator and air
pumps. Mounting a boiler with sufficient size and capacity to heat
a train required extending the SDP’s rear frame and deck as well
as extending and widening the long hood. The frame extension was
also adapted to make physical contact with the diaphragm plate on
the first passenger car behind the engine, a practice carried over
from steam passenger locomotive design.
As a passenger engine, the
SDP-35 did not need to carry the large quantity of fuel required
for freight operations, but it did need to carry water for the
steam boiler. As was EMD’s practice with first and second
generation passenger diesels, the SDP-35’s fuel tank was
actually two tanks, with the front tank for diesel fuel and the
rear one for water. Of
course, the boiler burned diesel fuel to generate steam.
Between 1964 and 1966, 360
SD-35s were built for US railroads with 35 SDP-35s built in ’64
In a communiqué with Jim
Weaver of Atlas O, he stated “Atlas’ penchant is scale models
. . .” and the exemplary detail in their models of the SD/SDP-35
show it. From individually applied grab irons and scale-sized
lifting rings on top of the long hood to sand pipes on the bottom
of the truck frames, small details abound, many of which are not
usually associated with mass-produced 3-rail locomotives.
At each end, the pilot has
individual MU cables, complete with connectors and right-angle
conduit molded in. Although the automatic coupler is the
obligatory oversized knuckle required for 3-rail operation, a
molded draft gear box covers its actuating coil. A moveable
coupler pin lift bar, formed from wire, is on the face of the
pilot with a molded plastic train line, complete with glad hand
connector and isolation valve handle, realistically mounted beside
Depending on the
locomotive’s road name, each SD-35’s pilot has either a
snowplow blade or brake-man’s foot boards, with the exception of
the SDP-35s, which have only a plain pilot beam behind the rear
truck. On the N&W engine, foot boards are at each end in
keeping with the road’s real SD-35s, while the UP SDP correctly
carries a plow on the front pilot. If the locomotive has a foot
board assembly installed on the front pilot, Atlas O provides a
separate snowplow blade, should you want to mount it. However, you
have to surgically remove the footboards from the pilot before you
can mount the plow.
Steps on the pilot and
battery box are perforated in keeping with the steps on real EMD
locomotives, as is the no-slip diamond pattern cast into the frame
deck walkways. Handrail stanchions, some of them individually
applied on the diecast frame, are the correct U shape, which
I’ve not seen before on mass-produced diesels. An operating
fold-down walkway bridge is on each end of the SDs, except on the
rear deck of the SDP, which extended to accommodate the steam
Brake pistons and separate
air lines mounted on the truck side frames again are details not
normally applied to moderately priced 3-rail locomotives. A sand
pipe mounts to the brake shoe hanger closest to the fuel tank, but
I found it rather curious that these pipes were not present for
the other wheelsets in each truck. The speedometer cable mounts
prototypically to the left journal of the front truck’s center
axle; a nice detail that is unique to the Atlas O SD/SDP-35s.
The fuel tank – oh what
a visual difference a scale-sized fuel tank makes on the SD-35. It
gives the realistic visual massiveness that is usually missing
from O gauge road diesels that have narrow and shallow tanks for
clearance with trackside obstructions, like Lionel switch motors.
On each side of the diecast tank is the correct fill pipe and cap
plus the sight glass, the visual indicator for fuel quantity. Even
the placard “TANK FILL” is correctly applied to the frame
above the fill pipe. On the SDPs, the casting appears correctly as
two tanks for diesel fuel and water. Nestled in the cove between
the fuel tank and the locomotive frame are the air reservoirs and
air lines. As is fairly standard for models of road diesels, the
fuel tank is the speaker housing for the on-board RailSounds
The Atlas SD-SDP-35s uses
a diecast frame rather than a more conventional one of pressed
steel. Atlas’ Jim Weaver explained that this frame adds needed
weight to the locomotive as well as working effectively with the
diecast fuel tank to provide better acoustics for the RailSounds
system. It also provides a rigid mount for the scale
cross-sectioned handrail stanchions.
Molded-in details on the
plastic body shell are crisp and precise enough to look great
under close scrutiny with a 5X optical viewer. Under this
magnification, door release handles are so realistic, they looked
like I could grab and pull them out of their recessed pockets to
unlatch and open the access doors to the prime mover. At the left
side of the front hood, the hand brake lever, gearbox, and chain
are nestled in their cove, looking like they are ready to crank-on
the brakes for parking the engine on a siding.
Formed wire grab irons are
separately applied, as are rooftop details such as lifting rings
and see-through fan housing grills, complete with moveable fan
blades visible through the grills. One note of caution – the
lifting rings on top of the hood are plastic and small, and as
such, even the slightest contact can shear them off. Separate
windshield wipers are correctly positioned over glazed windshields
and door windows while two crew members are at their posts inside
the enclosed cab.
On all versions of the
Atlas O SD/SDP-35, the prime mover cover, with its integral
dynamic brake resistor housings, is a separate molding and is
removable from the main body. Jim Weaver explained that this
separate molding models the crisp relief and appearance of the
prototype resistor housings and is not intended for access to any
of the locomotive’s internal components.
At the back of the SDP-35,
the long hood extends rearward and protrudes out to the left side,
modeling the housing for the steam boiler. Additional separately
applied details on top of the hood depict the boiler flues and
safety valves as well as the cap for the rear sand hopper.
Removing the body shell to
install the RailSounds support battery, or for maintenance, is
relatively easy and is adequately illustrated in the owners
manual. Six small screws hold the body to the diecast frame, but
unlike most contemporary models of road diesels, the handrails
attach primarily to the frame, with their ends inserted into the
cab. You have to disconnect the handrails from the cab and use
care to prevent scratching the paint as you lift the shell free of
the frame, not at all unlike working with Lionel road diesels made
in the 1970s. In this particular situation, I’ve found inserting
business cards or similar small pieces of card stock between
handrails and the painted cab works great in protecting the paint
during removal and installation of the body shell.
Spring pressure contracts
on the body and frame electrically connect the body-mounted light
bulbs to the frame-mounted electronics; there are no cables to
disconnect during shell removal or wires to worry about pinching
Paint and Graphics
Overall finish on both
locomotives submitted for this review is near perfection, smooth
with a soft satin luster that hides none of the fine molded
details on either the frame or the body shell. Lettering and graphics are crisp and precise and, as best I
could determine from photos I found on the World Wide Web, are
prototypically correct for both locomotives. On the N&W,
yellow-painted “safety” handrails correctly flank the steps at
each end of the frame.
On the Union Pacific
engine, I noticed some hand-done touch-up of the yellow paint
across a few of the access doors on one side of the long hood
(remember the 5X optical viewers I mentioned several paragraphs
ago). I suspect this touch-up was to correct some minor masking
bleed-under of the red paint into the yellow, but in normal light
and viewing distance it was imperceptible.
On each truck, a can motor
drives the center axle using a worm and gear, with spur gears
transferring torque to the wheelsets at each end. Wheels on both
ends of the truck are flanged and, although Atlas O ships each
SD/SDP-35 with the center wheels blind, no flanges, the company
also includes an extra center axle assembly for each truck,
complete with flanged wheels and the drive gear. Experienced
modelers who want to run all wheels flanged can replace the center
I emphasize “experienced
modelers” because Atlas does not include any documentation or
instructions for swapping the axles. It’s not a difficult job,
as only a number 0 and 1 Phillips screwdriver plus a bit of study
of the power truck design are really necessary. Personally, I
consider the design of the power truck one of the best I’ve seen
for mechanical operation and integrity as well as for effecting
modification or repairs, without special tools. The truck block is
essentially two halves that split horizontally across the center
line of the axles. Recessed machine screws hold these halves
together, so no wheel puller or press are required to change
axle/wheel assemblies, or to replace a damaged part.
Traction tires on the
wheels closest to the pilots, as well as on the center wheelsets,
work well under most track conditions. However, if your layout
includes Lionel automatic switches, the traction-tire-equipped
lead wheelset may not conduct electricity from the common to the
control rail for actuating the anti-derail feature of the switch.
If you need all-metal lead wheels, you can disassemble the truck
and swap the axles from one end to the other. This modification
puts metal wheels at the pilot end of the truck with the traction
tire wheels next to the fuel tank, and you’ll most likely need
only to modify the engine’s front truck.
While I’m on the subject
of the power trucks, should you want to separate the motor from a
power truck for whatever reason, you’ll need to remove three
screws: two screws holding the AC hot and common power wires to
the top of the truck (next to the motor) and the large screw from
under the truck that normally secures the motor to the truck. The
two screws that hold the wire terminals also hold the motor base
plate to the top of the truck.
Since the diecast frame
for the SD/SDP-35 is rather soft, as is any diecasting used in
model railroading, Atlas O assembles a steel plate to the frame
above each truck to serve both as a bearing plate between the
truck and the frame and as a reinforcement. This engine is really
Electronics, Lights, and Sounds
TrainMaster Command electronics control the motors and directional
lighting, including headlights, illuminated number boards, and red
rear marker lights. Freight engines have number boards and marker
lights at both ends with headlights and number boards lit on the
forward end and red markers lit at the rear, depending on the
engine’s direction of travel. Passenger engines have headlights
at both ends but number boards and marker lights are only on the
front of the engine with the markers lighting only when the engine
is running in reverse.
RailSounds 4.0 produces
sounds of a GM diesel prime mover, very close to those reproduced
on Lionel’s GP-9s. But then, the SD-35’s turbocharged GM 567
is the same basic diesel used on the early Geeps, so similarity
between the two types of engines could reasonably be expected.
Considering the size of
the speaker located in the fuel tanks, reproduction of the prime
mover, horn, and bell sounds is good with the characteristic
strong bass resonance that I’ve come to expect from diesel
RailSounds. Simulated radio chatter is unintelligible, in keeping
with other RailSounds crew chatter that I’ve listened to.
No smoke unit is included
with the Atlas O SD/SDP-35s, and after taking the body shell off
the frame, I could see why – no room for one exists. As for
myself, the lack of smoke unit doesn’t bother me, since the only
time I ever run one of them is to report on it’s out-put. You
see, smoke and I don’t get along all that well.
The first time I eased the
CAB-1 throttle open on the SD-35, I was immediately impressed with
a smooth and effortless startup and run around the layout. Gearing
is quite low and response to the CAB-1 throttle is outstanding –
in fact, if the SD/SDP-35 is not the most responsive engine that
I’ve tested in quite a while, it’s right up there with the
best of them.
With the engine stopped
and its sound system reproducing prime mover idle at full volume,
the electronics pulled 0.5 amps. Its maximum effective tractive
effort, without driver slip, measured a respectable 2 lbs. 9 oz.
At 10 volts and drawing 4 amps. The 20-car test train that I chose
for exercising the N&W SD-35 consisted of weighted scale 40’
boxcars that took about one pound of pull to get under way. So
needless to say, the big black N&W had no problem with its
train. At 60 scale miles per hour the SD drew 2.75 amps at 12
volts from a ZW, running in conventional mode of course.
Speaking of the N&W
engine, it defaults to starting short-hood-forward. According to
Jim weaver, the economics of mass production inhibit special motor
wiring for one variant of a product line, such as the N&W
SD-35, and Lionel’s electronics do not yet support an external
switch for setting an engine’s start direction. However, a
prototype-conscious owner can easily swap polarity of the two
wires to both motors so the engine starts in the proper direction.
Six yellow and gray UP
heavyweight passenger cars plus a scale UP express boxcar were the
test train for the UP SDP-35 and again, the engine had no trouble
pulling its load. Plus, the matching engine and cars made for a
mighty attractive train, especially to a certain product reviewer
and UP fan – me.
Both the SD and the SDP
ran well and tracked without problems on all three loops of the
editorial Carpet Central: O42,
O54, and O72 tubular sectional track, with Lionel O72 turnouts.
With the engines running through the tighter turns, there was the
expected slowdown because of their long wheelbase trucks, but I
didn’t consider it at all objectionable. I also understand that
Atlas O extensively tested the engines on several brands of track
to ensure correct operation.
One of my initial concerns
about operating was the size of each engine’s fuel tank and its
apparent proximity to the rails. But after the big SD’s first
run around the Carpet Central, my concern obviously had no
foundation. In fact, throughout the next several hours of
operation, with some of them over very uneven temporary roadbed,
that beautiful wide and deep tank never contacted the rails.
Coil coupler operation was
flawless, even at low track voltages not normally used for Command
operation: 8 to 10 volts. And running both engines in a double-head
lash-up was as much fun as running them solo – well, actually it
was even more fun! As in solo Command operation, the lash-up’s
response to CAB1-1 throttle control was precise and predictable.
From unpacking the
SD/SDP-35s for this review to repacking them for shipment to OGR
Editor Fred Dole’s photography studio, I found Atlas O’s new
road diesels downright exciting; not only for their faithful and
abundant detail, but also for their smooth running and strong
RailSounds 4.0 sound system. Best of all, the well-thought-out and
executed mechanical engineering, primarily the on the frame and
power trucks, make these engines truly unique within the hobby.
These two locomotives not
only met, they vastly exceeded all of my expectations that I
mentioned at the beginning of this article. Both the N&W SD-35
and the UP SDP-35 were a pleasure to just gaze at, to study
closely, and especially to run.