DrewKnight said:
We took my wife's parents up the Cog (old coal engine, which was just what they wanted) two weeks ago. I asked the brakeperson on our train how much coal it takes to power one of the old engines up the mountain. She said, "About a ton." I asked how much diesel the new engine required for the same run. She said, "About 8 gallons."
In economic terms, that puts a run on coal at about $250, versus about $50 for biodiesel. I'll leave it to someone who's better at math to calculate the reduction in environmental impact -- but in terms of carbon output, etc., it has to be huge. My in-laws were thrilled with the entire trip -- right down to the coal-cinders blowing in the window -- and the nostalgia of it certainly is worth something in the world. That said, it's hard to say the new engines aren't a big win.
Pasted below is an article from a technical journal concerning the Cog Diesel. It it is indeed quite technical. However, it does answer many of the questions people have been asking including how much fuel it uses on each trip. I also found the details on the 'braking' system to be very interesting.
Steam Engines Switch to Bio-Diesel Hydraulics on Mount Washington
Ron Ruel and Don Warren, Contributing Writers -- Design News, September 17, 2008
Since the first locomotive excursion to the top of New Hampshire's Mount Washington on July 3, 1869, steam power has been in use at the Cog Railway for climbing the mountain's steep grade. But now the funny little engines with tilted boilers, balloon smokestacks and special gearing, plus a ratchet to keep them from rolling backward, are going through their first design change since 1875.
Replacing the soft coal boiler and steam-driven Cog drive design on the locomotives with a modern bio-diesel-powered hydraulic drive system delivers a variety of benefits. Fuel efficiency and energy recovery for the braking systems saves several hundred dollars per trip to the summit. Eliminating the licensed inspections of the boilers that cost $100,000 per year reduces maintenance expenditures. Replacing the boilers reduces smoke emissions, and additional redundancy and new capabilities for each locomotive enhances an already pristine safety record.
Preserving the charm of this famous White Mountain tourist attraction was a critical goal of the design team during the conversion to diesel and hydraulic power in the first new locomotive. But the Mount Washington Cog Railway (MWCR) still plans to use a fleet of seven coal-fired locomotives and has no plans to completely eliminate the steam-driven trains.
In August 2006, a team of engineers met at the MWCR and determined that the new, environmentally friendly, energy-efficient locomotive would feature two hydraulic systems. A Parker Denison hydrostatic pump/motor drive system, powered by a John Deere diesel engine, would be developed to power the train during its assents. A separate hydraulic system would provide non-friction braking during descents. Both systems would be controlled by a Parker IQAN control and energy management system.
The new locomotives will reduce energy use by about 90 percent. Instead of burning a ton of coal at approximately 15,000 BTU per pound for a total energy use of 30,000,000 BTU per trip, the diesel/hydraulic locomotives will use 17 gal of bio-diesel (B-20) fuel for each trip to the summit and back. Bio-diesel fuel significantly lowers emissions, as well. Coal produces about 1,500 lb of carbon pollution per trip and the bio-diesel a mere 89 lb of carbon pollution per trip, a 94 percent reduction.
Initial trials began last year and the new locomotive was scheduled to be officially unveiled to the public at a ribbon-cutting ceremony in September 2008.
Diesel and Hydraulic Power Train Drive
The new bio-diesel locomotive's power train consists of a John Deere PowerTech 6125H 600 hp diesel engine, which drives a triple pad Funk 56000 Series PTO (Power Take Off) pump drive. This drive was designed to operate in side tilt and steep incline applications without damage to the gears and bearings.
Two Parker Denison Goldcup (P14) hydrostatic pumps provide electronically controlled variable pressure and flow to two Parker F11-250 fixed displacement, axial piston hydraulic drive motors. They are coupled to two 1000 Series Eskridge planetary gear boxes that drive the locomotive's two Cog gears, under the locomotive, for going up and down the mountain.
The average grade of the railway is 25 percent, or 1,320 ft, per mile. At the railway's 300-ft trestle called Jacob's Ladder, the grade is 37.4 percent which means the train rises about 37.4 ft for every 100 ft it moves horizontally. This steep climb requires power and capitalizes on a fundamental advantage of hydraulics when it comes to power density.
Hydraulics Control for Braking System
Power is required when coming down the mountain, as well, ensuring the train safely descends at a slow speed and in complete control. Bolted to the third pad of the Funk PTO is a Parker Denison fixed vane hydraulic pump that runs unloaded during the train's assent, but is used as a brake during descent. A proportional relief valve controls the pressure of this pump, which induces a load on the power train and applies brakes for both the locomotive and the coach during the return trip down the mountain to the station.
A spring applied to a Bendix brake is used for fail-safe braking and a Parker Skinner valve controls the air to this braking system. A pneumatic parking brake is engaged when the spring applied brake is not engaged. There are four cogs in the braking system; two for propulsion and two for the pneumatic spring applied fail-safe and normal parking brake systems. The train has four times the required redundancy for safety systems.
Integrated System Control
A Parker IQAN-MDL electronic control system provides integrated system management for the locomotive's diesel engine, hydrostatic drive system, braking system and cooling systems. In addition to functioning as a master controller displaying information and providing a data gateway, the MDL has a variety of flexible i/o channels and two Parker XA2 expansion modules.
The electronically governed diesel engine was selected because it is compatible with SAE J1939 technology. This enabled the engineering team to integrate the Parker IQAN control system with the engine and other power train components. Using J1939, the control system gathers vital engine data from the engine's J1939 CANbus protocol and monitors parameters such as engine speed, oil pressure and cooling water jacket temperature.
All of the information generated by the diesel engine is transferred directly via a simple connection through two wires where it can be monitored, analyzed and displayed. Multiple screens display data including vehicle speed, angle of inclination, train location, vibration and hydraulic filter status.
The IQAN control system also helps keep the locomotive operating at optimum levels by the monitoring of hydraulic systems and alerting operators when maintenance is needed. For example, the MDL constantly reads pressure transducers that monitor pressure levels of vital hydraulic functions. If pressures are either too high or too low, the MDL is programmed to execute a slow down or shut down of the locomotive to avoid or minimize damage to the troubled system. There are several optical fluid level sensors in the hydraulic reservoir so, if there is a hydraulic leak, the MDL alerts the operator before a critical amount of fluid is lost.
To ensure hydraulic fluid remains clean, Parker implemented its ICOUNT system to measure dirt particles in the fluid from the drain of the two hydrostatic transmissions. If the particle count becomes too high, the MDL alerts the operator and slows the train before critical damage to the transmissions results.
The control system also controls the emergency stop (e-stop) and emergency braking systems. If there is a critical hydraulic and/or engine parameter failure, the MDL will stop the train immediately (within 10 ft). If necessary, one operator holding a wireless multi-button pendant could control the locomotive and passenger coach from the coach because the MDL is capable of reading a signal from a RF remote control system on the CANbus (via the use of Enrange radio transceivers).
All Aboard for the Summit
The new bio-diesel/hydraulic locomotive illustrates how the Cog Railway is meeting new challenges and adapting to changing times. But even with the introduction of modern technology, it still has the look of the early steam engines that climbed the railway to the mountain's summit years ago. Maintaining tradition and 19th century charm is vital for the Railway's continued success - even as a new version powered by bio-diesel and hydraulics becomes part of a nearly 140-year tradition.
Ron Ruel, M.E., is a sales engineer for The Leen Co., a division of the Hope Group. Don Warren is a hydraulic territory manager for Parker Hannifin Corp.
© 2008 Reed Business Information, a division of Reed Elsevier Inc. All rights reserved.
