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Bachmann HO scale Baltimore & Ohio EM-1 2-8-8-4 steam locomotive

Read this review from Model Railroader
Bachmann HO scale Baltimore  Ohio EM1 2884 steam locomotive
Bachmann HO scale Baltimore & Ohio EM-1 2-8-8-4 steam locomotive
A Baltimore & Ohio EM-1 2-8-8-4 is available for the first time as an HO scale ready-to-run plastic model. The Bachmann Spectrum series EM-1 includes a dual-mode Digital Command Control (DCC) decoder that operates on direct-current (DC) and DCC layouts. To add sound effects and more programming capability, a SoundTraxx DCC sound module is available separately.

The prototype. During World War II, the Baltimore & Ohio RR was unable to get approval for an order of new diesel-electric locomotives from the War Production Board. The B&O instead settled on what would be its last group of articulated steam locomotives. Designated EM-1 by the B&O, the massive locomotives had a 2-8-8-4 wheel configuration, weighed 628,700 pounds, and could develop 115,000 pounds of tractive effort. Baldwin Locomotive Works delivered nos. 7600 to 7609 in 1944 and nos. 7610 to 7629 in 1945.

The first assignment for the EM-1 class was hauling coal and fast freight on the Cumberland Division between Cumberland, Md., and Fairmont, W.Va. After B&O dieselized that division in the 1950s, the EM-1s hauled coal from West Virginia to Cleveland and Lorain, Ohio. Some of the engines worked on the
Pittsburgh Division’s Johnstown Branch.

In 1957 the EM-1s were renumbered 650 to 679, and by 1960 all were off the B&O roster and eventually scrapped. Three survived for a few more years supplying steam for an Ohio chemical plant in the early 1960s; none of the locomotives were preserved.
The model of no. 7627 has correct small sand valve covers. The check valve should be in front of the dome
The model of no. 7627 has correct small sand valve covers. The check valve should be in front of the dome.
The model. The dimensions of the Bachmann EM-1 match prototype drawings published in January/February 1981 issue of Mainline Modeler.

Most of the molded detail on the model matches prototype drawings. However, the locomotive tender is missing the access door on the fireman’s side.

The many separately applied details are a highlight of the model. These parts include virtually all piping and handrails, as well as the distinctive overfire jets along the sides of the firebox.

The lettering on the model is clearly printed and correctly positioned. Crew figures and gauges and valves on the boiler backhead are also neatly painted.

Spotting differences. Our review sample models no. 7627, one of the EM-1s built in 1945. I appreciated that Bachmann used the correct five-sided Baldwin builder’s plates on the smokebox. An EM-1 built in 1944 would have had the older style circular plates.

The main spotting difference between the 1944- and 1945-built EM-1s are the sand valve covers on the sides of the boiler. The first group had large covers, while the second group, including no. 7627, had small covers. The boiler check valve on the engineer’s side was also relocated to the boiler course ahead of the front sand dome. Bachmann’s model of no. 7627 has the correct small sand valve covers, but the check valve is incorrectly in the early (1944 group) location.  

A pair of sand filler hatches was located side by side on top of each sand dome on the first few EM-1s. Starting with no. 7609, the hatches were placed along the centerline of the boiler. The hatches on the HO scale no. 7627 are incorrect for its prototype.

Most EM-1 locomotives had single headlights. During the 1950s some EM1s received dual headlights, as depicted on the model. A user-installed single headlight is also included.
The SoundTraxx sound module sold separately fits onto a 21-pin plug on the printed circuit board inside the tender
The SoundTraxx sound module sold separately fits onto a 21-pin plug on the printed circuit board inside the tender.
Mechanism. The motor and brass flywheels are housed inside the locomotive boiler. Two ball-and-socket drive shafts transfer power from the motor to the second axle on the front engine and the third axle on the rear engine. Side rods transfer power to the other drivers.

Both engines on the model pivot to allow it to maneuver around curves with a radius as tight as 22". On a prototype EM-1 only the front engine pivoted.

A two-wire and four-wire harness run from the decoder in the tender to sockets under the locomotive cab.
Bachmann Trains HO scale EM-1
Speed tests. I tested the model on DC with a Model Rectifier Corp. Tech 4 power pack. The sounds and lights came on at 6 volts. However, the model didn’t start moving smoothly until I’d applied 9.5 volts to the track. I didn’t find any mechanical binding to explain this. The model then accelerated smoothly to its top speed of 60 scale mph at 12 volts.

The model performed better when I ran it with an NCE DCC system. After I set the decoder to 128 speed steps, the EM-1 crept along smoothly and quietly at 1 scale mph in speed step 1.

The Bachmann decoder features some programmable configuration variables (CVs) for changing the locomotive’s address, starting voltage, and acceleration and deceleration rates. I also turned on the locomotive headlight with function 0 and dimmed the headlight with function 1. The backup light automatically turns on and the headlight dims when the model is set for reverse. This also occurs on DC layouts.
Price: $365

Bachmann Trains
1400 E. Erie Ave.
Philadelphia, PA 19124

Road numbers (all Baltimore & Ohio): no. 7627 (with dual headlight, small sand valve covers),
nos. 7600, 7604, 7614 (with single headlight, large sand valve covers). Unlettered versions available.

Era: 1945 to 1957 (as detailed)

  • Electrical pickup on all drivers and tender wheels
  • E-Z Mate Mark II knuckle couplers at the correct height
  • Five-pole skew-wound motor with brass flywheels
  • Light-emitting diode (LED) headlight and backup light
  • Metal RP-25 wheels in gauge
  • Weight: 2 pounds 4 ounces (locomotive and tender),
  • 1 pound 91⁄2 ounces (locomotive alone)
SoundTraxx sound module. To install the SoundTraxx sound module (sold separately) I removed four screws from the tender’s frame and lifted off the tender shell. Inside is a printed-circuit (PC) board with a 21-pin plug. The factory-installed speaker and enclosure is mounted under the PC board. Following the instructions, I carefully inserted the module into the plug and then reinstalled the tender shell.
In DC and DCC speed tests the model performed the same as it did prior to the sound module installation. In addition, when I operated the model with a DCC system, I now had many more programming options, including 14 preset speed tables. For extensive user manuals that list all the programmable CVs, visit the Bachmann or SoundTraxx websites.

The excellent sound quality is on par with other SoundTraxx sound decoders. User-triggered functions include a bell, long and short whistle (there are three different whistle types to choose from), and coupler crash. Function 6 triggers a water stop sequence. In addition to a built in seven-band equalizer, the module supports CVs for adjusting the individual volume levels of each sound effect.

I especially like the sound module’s Dynamic Digital Exhaust feature, which varies the intensity of the chuffing according to the load on the locomotive. The DDE section of the instruction manual is especially helpful and explains how to fine-tune the effect.

When I ran the sound-equipped model on a DC layout, the exhaust sounds were unsynchronized to the
locomotive speed. This can be fixed by adjusting CVs, but to do so requires a DCC system or a DC sound controller, such as the MRC Tech 6.

Bachmann did a good job modeling the EM-1 and got most of the details right. Especially with the SoundTraxx sound module installed, this HO scale model brings one of the steam era’s last and largest locomotives to life.
Price: $119

Manufactured for Bachmann Trains by SoundTraxx
210 Rock Point Drive
Durango, Co. 81301

  • 16 bit sound processor
  • Built-in seven-band equalizer
  • Designed specifically for the Bachmann EM-1
  • Maximum track voltage: 27V

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