There and Back Again: A Transportation Technology's Tale

With respects to JRR Tolkien, whose writing I greatly enjoy (Peter Jackson's movies somewhat less), I have been thinking about the changes in the infrastructure of transportation technology since a visit to the San Francisco Cable Car Museum a few weeks ago. I recommend it for a great short visit. It has history of the cable cars and the 1906 Great San Francisco Earthquake & Fire, lots of historical pieces, and the mechanism that actually drives today's remaining cable car lines. Even better, it is free, which is quite a treat in the very expensive San Francisco.

The cable car was introduced by Andrew Hallidie, inventor and public figure, in 1873. Before then, like every other city around the US (as well as the world), public and private transportation were provided by horse and carriage, or foot. However, as SF expanded from the edges of the Bay, it encountered those famous and beautiful, but difficult to climb, hills, for which the city is famous. Many horses could not get up or down the hills, let alone pulling a carriage full of people behind them. Those that could were more expensive, burned out quickly, and left quite the residue behind for the city to clean. All in all, horses were a very expensive and inefficient - not to mention barely effective - proposition.

Hallidie recommended using the then-becoming-effective electricity to drive a few key stations, where huge wheels would cause the cables to move under the streets at precisely 9.5 mph (15.2 kph), and cars could move by gripping the cables.

Within a few decades, however, electricity distribution had caught up in efficiency to electricity generation, which had enabled the entire cable car system in the first place. Putting an electric engine into the car and letting it draw electricity from wires under the ground or overhead - what most of the world calls a trolley - became more efficient than cables under the street. When the great earthquake destroyed much of the cable car infrastructure, it made much more sense to invest in trolleys, rather than cable cars. SF almost lost them all, until they were declared a National Heritage and, thankfully for pictures and movies and tourists, the few remaining lines have been retained.

Finally, unlike SF, most cities have eventually moved to completely independently-powered trolleys, without cable lines overhead. We call them buses.

What I find fascinating is how the development of transportation technology went full circle.

1. Fully Independent: Each unit moves under its own power - literally, horsepower
2. Fully Centralized: New power generation - electricity - surpasses the old independent power, leading to central power and locomotion, i.e. cables
3. Semi-Centralized: New power distribution and locomotion efficiency begin to overtake centralized locomotion, and the engine is moved back into independent units, with power provided centrally, via overhead or understreet lines - trolleys
4. Fully Independent: Power generation and locomotion fully overtake centralized, with self-powered units - gasoline buses

Whether the next state is electric buses, or gasoline buses, or liquified natural gas (LNG) buses, the final state remains independent units moving down city streets under their own power, with no central distribution of power or locomotion.

Just about every other system that depends on power works this way. Right now, with home lighting and powering, we are in the semi-centralized state. Houses (in the modern era) were originally lit with oil and heated with wood or kerosene. Nowadays, most are done by electricity, but the distribution is provided via a central network. This makes each home highly susceptible to the network - as several outages in the last decade have shown - and exposes each one to surges from the others.

Will home power generation eventually go the same way as transportation?

It is hard to tell. Most home units cannot support a wind turbine and do not have a major waterfall on their property. Solar is growing, but still low efficiency and more expensive than coal/oil/LNG-generated power. But if trends hold, eventually each home or at least neighbourhood will become independent in power, similar to each car being independent in transportation.