To our younger readers, HO scale locomotives with smoke units may seem like a recent development. In reality, the feature dates back to the end of World War II when American Flyer began producing 1:87.1 steam locomotives with smoke.
Since that time, companies have continued to offer HO locomotives with smoke units. Admittedly, some manufacturers have done it better than others. Thanks to advances in technology, today’s modelers are enjoying smoke units that are synchronized to the drivers. Perhaps the next step in smoke unit technology will be the ability to produce thick, billowing plumes instead of wispy white streaks.
Smoke-equipped locomotives tend to divide modelers into one of two camps: Those who find it neat, and those who think it’s a gimmick. Regardless your point of view, there’s no denying that HO scale locomotives with smoke units have enjoyed a long run.
Steam locomotives with smoke units
When I joined the Model Railroader staff in 2002, we were just starting to see a resurgence in off-the-shelf HO scale locomotives with smoke units. Steam locomotives, naturally, were (and continue to be) a popular subject. One of the first models with a smoke unit I recall from this era was the Broadway Limited Imports Southern Pacific 4-8-8-2 Cab-Forward. A fan-driven smoke unit was one of the upgrades to the steam locomotive. You can read former senior editor Jim Hediger’s review of the Cab-Forward in the December 2004 issue of Model Railroader.
MTH Electric Trains had long been a leader in O gauge when it entered the HO scale locomotive market in 2006. The company’s first 1:87.1 model, a Pennsylvania RR K4 Pacific, showed how sound and smoke could work in unison. “A great smoke unit is built into the boiler, and it’s timed to match the chuffing sounds,” Hediger wrote in the July 2006 issue. “It has a small fan that delivers four realistic puffs of smoke for each driver revolution.”
Bachmann Trains, Broadway Limited Imports, Märklin, and Trix are among the companies that offer steam locomotives with smoke units today. Models from BLI feature synchronized puffing smoke with chuff sound and variable puffing smoke intensity and timing.
Don’t forget the diesels
Though not as common, HO scale diesels with smoke units are around. In the July 2012 issue we reviewed the MTH Alco PA and PB diesels. The cover line in the upper right corner even proclaimed “New MTH diesel smokes.”
Once the heating element warmed up, a fan-driven unit pushed a stream of white smoke out of the exhaust stack of the six-axle passenger unit. The feature could be turned off using a switch under the fuel tank.
If you’re in the market for modern era diesels with smoke units, you have a few options. Broadway Limited Imports offers its Electro-Motive Diesel SD70ACe and General Electric ES44AC with a smoke unit.
Märklin also offers a General Electric ES44AC with a factory-installed smoke generator. The newly tooled model has an mfx+ decoder and is scheduled for release this month.
Smoke fluid
If your HO scale locomotive has a smoke unit, you’re eventually going to need more smoke fluid. Never operate a smoke unit if there’s no fluid in the reservoir, as this will damage the heating element. If your locomotive is out of fluid, turn the smoke unit off using the switch on the bottom of the model or adjust the configuration variables as outlined in the instructions.
The photo above shows six examples of unscented fluid that’s designed for all scales. Most of the bottles have an eye-dropper cap or screw-on funnel so the fluid is easier to dispense. An eye dropper or pipette can also be used to neatly add smoke fluid to locomotives. Most manufacturers note how much fluid is required in the paperwork with the model. For example, BLI recommends three to four drops, enough for 15-20 minutes of operation.
If you want the smoke in your locomotives to be seen and smelled, consider using scented fluid. At the Kalmbach Hobby Store website we carry a selection of products from JT’s Mega-Steam. The fluid is designed for HO and O scale models. Among the scents are coal-fired steamer, hot chocolate, coffee, and grandpa’s pipe smoke.
Smoke units
Over the years, some companies have offered steam locomotives that were designed for modeler-installed smoke units. For example, BLI’s 2004 release of the SP Cab-Forward was marketed as “Seuthe smoke unit ready.” An advertisement for Athearn’s Union Pacific 4-8-8-4 Big Boy in the April 2007 MR noted the model was “Smoke unit ready with no soldering required.”
The image above shows two smoke unit kits. Märklin No. 7226 (left) consists of a smoke generator insert, replacement smoke tube, cleaning wire, and tweezers. The kit is designed for select Märklin locomotives.
At right is Seuthe steam generator kit No. 99. The unit, with an operating voltage of 8 to 14V, is designed for all types of locomotives with plastic bodies. The kit includes a smoke unit, 10ml of smoke fluid, two syringe collars, and a syringe for adding the fluid to the model.
Seuthe produces a variety of steam generators for HO scale models. Some kits are universal, while others are manufacturer- and model-specific. Other items to note with Seuthe products are the operating voltage and what material(s) the smoke units is compatible with.
