The Cedar Rock Railroad is the home of Sophie, our first locomotive. She was built in 2001 to run on 16-inch gauge tracks as a 4-4-0 design with the locomotive drive wheels providing all tractive effort so she actually operates like a real locomotive pulling her train (rather than being an empty dummy pushed by the tender).
The intent behind her design was to visually mimic the real locomotives of the 1870s. With a hand-made wood cab following official Baldwin locomotive blueprints, and a unique smoke system that puffed in sync with her realistic chuff sounds, many people would ask if she was a live steam locomotive. The paint scheme we chose for her was also intended to show off her proportions and elegance, and it was so admired, many locomotives built later by other manufacturers had a near exact copy of her original paint scheme of red-capped stack and accessories, black boiler, and silver smokebox (search the web, you'll see many of them).
For us, her only shortcoming was the gasoline-hydraulic drive originally placed in her tender to drive the hydraulic motor on her drive wheels which was basically the standard at the time. Sitting above the engine in the tender, the noise, vibration, smell, and heat became extremely distracting, then annoying, then troublesome for the operator to maintain and repair. Passengers quickly realized she wasn't real steam as soon as we turned the key on.
So in 2011, we pulled all that grimy, greasy, smelly junk out!
Initially we used low-tech lead-acid batteries for proof-of-concept and low cost and also kept the indirect chain drive to get the power from the motor to the drive axles.
The good news was that the system worked beautifully and pulled full trains all day long on one charge!
There was no more heat, noise, smell, vibration, spilled fuel or leaking oil and our regular passengers immediately noticed the improvement. The ride was smooth and was much more inviting to ride.
And although the improvements were very satisfying, the weight and range limitations of the lead-acid batteries became apparent. So we researched the latest developments in traction-battery technology and experimented with a few competing options. After a few trials, we selected the Lithium Iron Phosphate (LiFePO4) battery chemistry due to its proven performance, safety, and reliability. The space and weight savings gained from the switch to LiFePO4 batteries was tremendous. For a battery pack with the same voltage and amp-hour rating, we reduced the weight by 55% and reduced the required space by enough to relocate the entire battery pack from the tender to inside the locomotive. Wow!
During the battery pack re-fit, we also redesigned the traction motor chain drive into a direct axle drive which allowed us to fit the entire system between the axles of the drive wheels - even at 16-inch gauge! It all fit perfectly and we had a completely empty tender carrying nothing but the driver at that point!
But the real pleasure came when we first applied the throttle....
All other systems were off so there was no locomotive sound or distractions.
We turned the key on and released the air brake.
The locomotive immediately held its position on the slope with the electric motor.
Then we slowly moved the joystick forward and began to roll...
It was COMPLETELY silent!
There was no hum, no ticking chain, or whining gearbox.
The only thing we could hear was the wheels rolling on the rails and it was exhilarating!
She finally felt like a real train!
And this "real" train is still operating faithfully today pulling full coaches of happy passengers.
Sophie is outfitted with the basic-level 13.8 KWh battery pack pulling two steel coaches on a 1.5 mile track circuit with 2% grade and curves as tight as 50-foot radius.The LiFePO4 battery pack with the direct-axle drive has proven to be an outstanding design and is capable of running up to four 8-hr days pulling full trains on just one charge!
Operators can quickly and easily see Sophie's operating status on the 7-inch color screen in her cab.