Curiouser and curiouser

Legacy Systems: Spaceships, Steam Engines, and Chariots

In 1829, Horatio Allen chose 5 feet as the track gauge, or distance between the tracks, for the new South Carolina Railroad. When completed in 1833, the railroad extended from Charleston to Hamburg, South Carolina, making it the longest rail line in the world and twice as long as any other American railroad. To build this revolutionary railroad, more than 1,300 laborers had to cut through swamps and forest, and construction costs were 38 percent over budget. Rework during the first 10 years of operation increased the cost to 3.3 times the original estimate, largely because of unexpected problems with new technologies in railroad design (Derrick, 1930). The South Carolina Railroad survived, but it achieved only modest economic success because of engineering and cultural problems (Vance, 1995).

To succeed economically, the South Carolina Railroad Company had to ship goods outside the state. These shipments were greatly hampered by the local government in Augusta, Georgia, which was near the end of the rail line. The South Carolina Railroad was not able to join its rail lines with railroads in Georgia because of lobbying by Augusta cargo handlers who moved cargo between the separate rail lines. This cultural barrier drove prices up and reduced revenue for the rail line (Vance, 1995).

Integrating rail lines was also inhibited by differences in track gauges, which were often chosen to foster economic protectionism. For instance, North Carolina refused to use the 5-foot southern gauge chosen by Horatio Allen, even though the southern gauge was used by railroads in Virginia to the north and South Carolina to the south. Instead, North Carolina used the incompatible "standard gauge" (of 4 feet, 8.5 inches) to insulate its rail lines from competition from railroads in neighboring states (Vance, 1995).

After the Civil War, the southern gauge was used throughout the South, and the standard gauge was dominant in the North. In 1886, the southern railroad companies held a convention in Atlanta, Georgia, to address concerns about competition from northern railroads. Motivated by the need to improve their competitiveness, the southern railroad operators, "in a display of amazing technical courage and confidence ... decided that more than 13,000 miles of southern gauge line would be shifted to standard gauge in a four-month period, with the actual narrowing of lines taking place on no more than two days, May 31 and June 1, 1886" (Vance, 1995).

The legacy of rail gauges, which extends much farther back in history, has had wide-ranging effects. In the 1970s, during the preliminary design phase for the Space Shuttle solid rocket boosters, Utah-based rocket manufacturer Thiokol Propulsion chose to move rocket booster sections from Utah to the Kennedy Space Center by rail. When evaluating the railroads, representatives from Thiokol Propulsion carefully checked tunnel and sidetrack clearances from Utah to Florida to ensure that the booster sections would pass safely. These clearances were one of the factors that determined the booster diameter of 12 feet, 2 inches (NASA, 1988; Shupe, 2000).

Clearance for railroad tunnels (see Figure 4-1) and switch-track sidings are determined by railroad car width and the standard gauge (of 4 feet, 8.5 inches), which U.S. railroads still use today (Harris, 1998). The standard gauge was based on the British railway gauge of the same measure established in the early 1800s. The British gauge was apparently determined by the track width of horse drawn carts, which were built to a standard width so that the wheels of each cart would fit neatly into the ruts formed by other carts. Archaeologists have found ruts worn into ancient Roman roads by centuries of carts passing over them. These ruts measure 1.44 meters (4 feet, 8.7 inches) wide, only 0.2 inches different from the standard railroad gauge used today in the United States (Margary, 1973; Von Hagen, 1967). These measurements, which suggest that the design of the U.S. Space Shuttle is based partly on the track width of ancient carts and Roman chariots, show the lasting influence of legacy systems.

-- Advanced Engineering Environments, phase 2: Design in the new Millennium, глава 4.

A member of staff has been seen exiting the G block lift containing a
liquid nitrogen dewar.

May we remind you that staff must not accompany dewars in the lift. If
you call a lift, the door opens and there is a dewar inside, you must
let the lift pass.

Liquid nitrogen must not be transported in occupied lifts because of the
danger of asphyxiation in the event of a leak or spill, especially in
the event of a lift breakdown.

One person should send the dewar on one floor and another should be
waiting to receive the Dewar from the lift.
Ideally you should place a barrier inside the lift across the entrance.
This warns any staff waiting for a lift who may not be aware of the
liquid nitrogen hazards.

Many Thanks
J Random Officer
Health & Safety
The Sanger Institute