Units Was: Where is balance 285

The Chicago & Northwestern is the railroad, but "English engineers" is not the reason.

Allow me to copy Wikipedia article on the CNW, which has the essence correct on this: (QUOTE) The CNW was known for running "left-hand main" on double track mainlines. In other words, traffic was routed by default to the track on the left rather than the track on the right. In the United States, most railroads followed the "right-hand main" operating practice, while "left-hand main" running was more common in countries where automobile traffic drove on the left as well. According to a display in the Lake Forest station, the reason for this was a combination of chance and inertia. When originally built as single-line trackage, the C&NW arbitrarily placed its stations on the left-hand side of the tracks (when headed inbound toward Chicago). Later, when a second track was added, it was placed on the side away from the stations so as not to force them to relocate. Since most pbuttengers waiting at the stations were headed toward Chicago, the inbound track remained the one closest to the station platforms. The expense of reconfiguring signals and switches has prevented a conversion to right-hand operation ever since. (END QUOTE)

Some additional comments: there is a reason for the stations being on the "left-hand side" for inbound trains---it has to do with Chicago-area weather. Suburbanites wait for inbound trains, a left-hand side station would be between the tracks and the prevailing north winds, affording some amount of protection from the elements for the pbuttengers. Not needed for outbound pbuttengers, as they disperse immediately on alighting.

Running trains "either way as needed to balance the traffic" requires "reverse signaling": such can be, and was, set up for some lines as far back as the days of mechanical interlockings (think VERY BIG finite state machines), and was also implemented with Centralized Traffic Control (CTC) which was developed with relay logic in the 1920s (or 1920's, as it would have been written then). There was long hesitation in the railroad industry to use computer systems to control signals as the relay logic had had a long history of included failsafe design (finally a link back to a.f.c.).

Bruce B. Reynolds, Trailing Edge Technologies, Glenside PA