A new transit system is being considered at the moment, but apparently only one type is being discussed - cars on rails. Installing rails is expensive, the result is a road that is dangerous to vehicles with narrow tires and pedestrians - and it is inflexible. The paths are literally set in stone (or at least black top). There are three other styles that ought to be considered, the rubber tired bus with a pantograph collection from overhead cables, the rubber tired bus with battery power and quick change battery trailer at the rear, and a composite bus with pantograph and small capacity battery to allow for switching from one cable route to another.

The bus with pantograph has a long history of success prior to the era of cheap oil and large mass-produced commercial vehicles running with internal combustion engines. They are cheap to maintain, quiet, with high acceleration and they do not alter the road surface. In Britain they slowly died away because their main components were not made in anything like the quantities of gas fueled vehicles. Eventually the company making spares died as a result of reducing numbers and the long life of the components. I believe the same was true in the USA.

Battery powered vehicles also have a reasonable history and motors and batteries have improved their efficiency over the past ten years or so (and promise to continue doing so). They are probably not as efficient in their use of electricity as the AC motor and pantograph, but they can be routed anywhere within the range of the batteries and the depots for charged battery .

Combining both seems an obvious answer, but I do not know whether it has been tried yet. The only advantage that rail has over rubber tired traction is a higher tractive efficiency - but it is not, I believe, a significant advantage.

Before Cincinnati begins tearing up road surfaces to install rails, or concrete 'guides' I think that the merits and availability of all systems, both now and in the near future, should be thoroughly investigated by the city's engineers.

Laurie Penman (mechanical engineer)

When I was a kid my family used to go to downtown Columbus for concerts/festivals/etc. I remember riding a sort of green trolley that was connected overhead to wires that would spark.

When the trolley had to switch from one wire to the next (like at a corner) it would coast for a moment, then the next overhead wire would be grabbed by the trolley antennae. I always wondered if the trolley would be stranded if it didn't coast all the way to the next wire. My older sister used to tell me that they would make us get out and push.

I remember that the trolley was completely silent, except for that rubber sound of tires. It felt like we were coasting effortlessly, and the cool breeze from the forward motion was wonderful on hot summer evenings.

Is this the "pantograph" system to which you refer? Can it be combined with batteries to propel it to the next wire if it needs to drive a block to grab the next wire?

Are there any companies currently producing these trollies?

Kate Harner