FUNDAMENTALS: (From high school days)
One Horsepower=746 Watts=550 Ft Lbs/sec
Energy is Ft Lbs. Power is Ft Lbs/sec
There is no free lunch. (Conservation of energy LAW)
A KWatt hour costs about 10 cents.
Power Corrupts!

ASPEN'S Wanna-Be Trolley:
Trolley as is weighs about 30,000 lbs empty, circa 1920.
Weight of 34,000 lbs with 25 160# passengers would take 600 pallbearers to lift it! All the power concerns are related to pushing this huge ironworks up and down the hill.
Currently, Two 25 HP motors, rated to go 25 MPH at 600 V DC Designed for overhead wires, acceptable in 1920, when most all wires were overhead, including telephone wires.
The route is about 2500 ft one-way, and climbs about 50 ft.
Maximum actual velocity is estimated at 15 MPH. Normally, 10 MPH
Average grade 50/2500=2%. Likely max of 6%
There are 13 stopping points/mile possible, rarely all used.

It is the HUGE weight of the trolleys (ala mining-era cast-iron age) that is the beastly burden we ask of the electricity, environment, performance, power consumption. RFTA wisely fights weight like wildcats. Their buses weigh about 1/4 as much per passenger.. It is worth lots of money to reduce weight. But, We may not have those funds now to trim our ships.

"MODEL" OF A 6 MINUTE ONE-WAY TRIP:
Ignoring traffic delays:
Four one minute segments, each 500 ft.
  10 secs to load a few passengers. (Sometimes longer)
  12 secs accelerating to 10 mph (15 Ft/sec)=4% of gravity.  90 ft
  20 secs 'coasting' at 10 MPH(15 FPS) avg (thrice a walk). 300 ft
  12 secs to decelerate  90/480 ft
A two minute 6% grade segment, rising 50 ft in 800 ft at 6 fps (4 MPH)   Requires 34,000x50/120=14,000 ft lbs/sec= 25 HorsePower = 25 KWatts
Average velocity is 1/2 mile in 6 mins or 5 MPH (twice a walk).

An acceleration of 4% of gravity, is equivalent to a force in the chest of 7 pounds for a 180 lb standing passenger. It is possible to accelerate more quickly than this, speeding up the trip. But, twice this is believed excessive, generating an overly 'lurchy' ride. More Acceleration requires more power for a shorter time, but does not increase energy consumption. It would demand a heavier power supply, as would climbing the hill faster.

The hill climb energy demand is 6% for 120 secs, the acceleration total is 4% for 50 secs. The coasting energy is likely 1% for 80 secs Thus, the climb is 75% of the energy needed. Also true for pedestrians.

There MUST be an intown car barn, for none would think seriously of returning the trolleys to the ABC RFTA barn nightly.

--------- POSSIBLE ENERGY SOURCES -----------
I'm in wonderment that one exhausted horse could lug a trolly up our hill in mining days (see this site), and suspect it stayed 'on the level'. Our present 6-tourist shay is NOT cast iron!

RFTA likes modern turbine hybrid electric drives, but likely to be a very costly retrofit.  Nifty if we could afford it. bares looking into.

Overhead wires have many problems and costs. They are publicly disliked enough to almost surely tip the delicate iffy chance we have from the electorate into an almost certain "NO THANKS!"

A trailed fuel-burning powerplant must deliver 40 KWatt surges, and is usually noisy, smelly, ugly, non-historic, unpopular, and I feel dangerously unexpected by strangers in cars/on foot. A redesign to a turbine hybrid trailer might be acceptable, but probably expensive enough to consider retrofitting the trolley internally. I get mixed reports about the trailer.

Steam, burning recycled Aspen Times and administration paper...Would have character..
Hydrogen fueled fuel cells. Not as nutty as it sounds. They are very efficient. Fuel carried aboard for the short trip. Batteries too for the evening-out of the power requirements, and for regenerative braking A hand-carried fuel tank/cartridge.. Hmmmmmm....Capacitors, Flywheels.. Forget em.  Nuclear... Not in this decade....

----------- MY PROPOSAL - BATTERIES! CHEAP ONES! A RELATIVE SNAP! ---------
Output required from direct batteries or controller :  At the design value 600 Volts and 50 HP (at 75% efficiency), the trolleys consumed 50KW, or 80 amps. This 30,000 ft lbs/sec at 25 MPH(40 ft/sec) delivered 750 pounds of thrust, 2.5% of the weight. Thus, if there were no friction, the trolley could have zooomed up a small slope at 25MPH! Way overpowered for us!

Because our max speed is only 15 MPH instead of 25. I would gamble that 250 Volts would comfortably propell the trolley with present motors! That is a huge help.

The electrical demand is much like car-starting. Auto batteries are cheap (but heavy) Gell Cells are better, a bit costly. Nickle-Metal Hydride is the choice of small devices, also heavy. Lithium is VERY light, but VERY expensive-used in costly high-performance electric bikes. High Current surges are the KEY parameter Batteries should last THREE years. I was in the computer UPS business, and that was our expectation for Gell Cells.  The LA electric TROLLEY uses them.

Controls primitive, easily remoted to both ends of the rolley, disguised as vintage trolley levers. 3 "Gears", Brakes (3 strengths), Fwd/Rev.  If this car is one of  three in circulation (one charging, two running),  we can EASILY run the system all day! As RFTA points out, a rail car can 'hitch up' automatically with low driver skills needed, for the train halts after a docking snubber with a tolerance of +- one inch!! Some cities use an inductive loop like an electric toothbrush (no contacts!), but I do not understand how cell phones could still work nearby! Again, to be investigated..

The charger circuitry could be in the barn, and wires laid to the charging sites. 
   1.----- LOWEST-TECH Battery System:  (Shamelessly without regenerative braking)   
By far the largest consumption is in climbing at low speed and accelerating. High Quality car batteries deliver 1000 amps cranking current at full voltage for 30 secs (CCA)!  For the 6 minute one-way trip: (estimates)
Climbing     6%   300 Amps for 2.0 Mins=600 amp.mins
Accelerating 4%   150 Amps for  .8 Mins=120 amp.mins
Running at 10 MPH 060 Amps for 1.3 Mins= 80 amp.mins
Braking & Loading 000 Amps for  .7 Mins=000/800 amp.mins = 14 amp Hrs/trip
Round trip is two trips. Battery consumption is only 30 amp hours/Round trip!

A standard 100 Amp-HR car battery could make three round trips!  I strongly reccomend only one round trip/recharge so we'd keep the batteries within operating charge levels.  SO! a 250 V battery without sophistication or any transistors (just diodes) can be only 20 ordinary car batteries, weighing perhaps 600 lbs, or 1/60 of the trolley! At 12"x8"x8" each, they'd fit a 3 foot x 6 foot fork-liftable tray, 1 ft high! Very high quality (1000 Amp cranking) Exides are $90 in small quantity, likely $60. Only $1200/ trolley! Could be trashed every season although I believe two years of operation is OK. Golf carts use 36 Volt batteries...  They are designed for just this type of service. Worth looking into... This option is based on 1940's technology without regeneration, to utterly minimize costs.

    Wild guess... $3000 per trolley. BIG Charger at $10,000


   2.---- ENHANCED LOWEST-TECH - Nick's INVENTION! -----
I have a scheme  to parallel batteries when starting/climbing, series them when running/coasting by the operator. Inexpensively. An almost exact analog to shifting gears in a car. This can cut the surge current problem by four times! And the conductor will feel more needed (of course, this could be automated). How would YOU like a car locked in second gear, like the trolley? And we'd add a try at manually switched regenerative braking, uncertain of it's effectiveness   Extra cost $600/trolley!


   3.---- HIGH TECH MODERN BATTERY SYSTEM, OLD MOTORS
Transistor motor controller drivers with regenerative braking, reducing battery demand by two or three times. Perhaps using low (96 volt?) battery system    If there were no friction or electrical resistance, we could hypothetically run the trolley for years on a flashlight battery! The passengers could pedal it! All 40,000 lbs! But, realistically a medium tech system can cut power cost and battery weight perhaps 50%. Smaller charger    Hip-shoot guess $10,000 per trolley.

   4.----- HIGHER TECH MODERN BATTERY SYSTEM, NEW MOTORS, LESS WEIGHT
Still higher up the techno-chain would be to REALLY lighten the trolleys with modern, more efficient motors. I was amazed to see that one can buy a new-technology premium efficiency GE 3 phase AC 25HP motor off the shelf at Graingers for $1100! It is comparatively tiny! AC motors like I use in the fountain make more sense today!  A rethink/rebuild of the trolley propulsion would use new motors (Much more efficient) and modern motor controllers. Designed for the optimum battery voltage, and tuned for maximum efficiency and re-chargeability.

The trolley weight would also be substantially reduced, minimizing battery consumption, shortening charging cycles, and perhaps even permitting a half day of battery life! Still Smaller charger Might cost $25,000 per trolley

ANTI-BATTERY CHARGES (DISCHARGES?)
There is a scare tactic statement that 600 Volts of batteries might "ARC-OVER" a dead cell and explosively wipe out bystanding innocents! I believe that is a contrived concern. Incidentally, a 6 volt battery could supply 20,000 volts to a power system, given 1980 technology. The power grid is riddled with such conversions.

On the subject of scares, an 8 ton battery recommended by an ouside "expert" to the Aspen Trolley gang is on the order of a twenty-five times exaggeration!  Could only have been calculated with an agenda. Or, calculated based on a full day's operation of 100 round trips on one charge. Goodness!

RFTA has NO prejudice against batteries. Just a bad experience with an unfortunately out-of date unfinished plan for an unwanted surplus old-technology electric bus that failed for non-electrical reasons. This experience did NOT persuade RFTA that batteries are evil! In fact, RFTA would love a state of the art system. RFTA's view is to "Do it Right". They seemed very reasonable, and would prefer an utter rebuild of powerplant to modern hybrid turbine-electric, replacing tons of iron, but might to be > $80,000/trolley. Calling for long-range vision and courage.

SUMMARY:
I believe the ONLY possible WINNING solution for our current trolleys is by battery. Low tech Batteries would be VERY inexpensive and smooooth. See above. High Tech Batteries (electronic controls) Likely way the BEST!  Our route would depend on our financial resources, immediate vs long-term vs operating expense. Any of the battery schemes can work   I do not know of any other power sources that can win the trolley for us!

               Nick De Wolf