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Don't know whether you're coming or going? Looking at some freight-train locomotives, you might think they were having the same problem, but you'd be wrong.
THE QUESTION: When you see a long freight train, it is often being pulled by two engines — the first pointing ahead and the second pointing backward. Why is the second engine running in reverse? asked Dan Ostler of Ajax, Ont.
THE ANSWER: "The efficiency of train operations depends upon being able to remake trains at their destination as quickly as possible," writes Jeff Smith of Calgary.
Diesel-electric engines, he says, run equally efficiently in forward or reverse. However, railways like to run the locomotives with the cab forward in order to maximize visibility.
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"The advantage of having the locomotives facing away from each other is that once a train reaches its destination there is no need to turn the locomotives around," either on turntables (which are rapidly becoming scarce) or using special rail configurations. This results in significant time-saving.
"The locomotive 'consist' (multiple joined locomotives) is simply removed from the incoming train and recoupled to a departing train. The controls are reconfigured to change the controlling end of the consist and the train is ready to depart."
THE QUESTION: Derek Hayter of Brampton, Ont., wondered why red and yellow sweet peppers are more expensive than green ones.
THE ANSWER: "Green peppers are mature but not yet ripe fruit of the pepper plant," writes Helene Robertson of Ottawa. "It takes more time and care to allow the fruit to ripen and turn to red, yellow or another colour." That time and care costs money, she says, and the cost is passed on to the consumer.
"The colour of the ripe fruit depends on the variety of pepper plant, but all are green when unripe."
FURTHER NOTICE
Following our item last week on why we adopted the Arabic number system, Alan Batten of Victoria writes: "Arabic numerals should really be called Hindu numerals, because they were first devised in India."
In particular, he says, the first recorded use of a sign for zero is in an inscription found in the city of Gwalior in northern India somewhat before the year 1000.
He says the Indian numerals were transmitted to Europe through the Arab-speaking Islamic empire, hence their name.
HELP WANTED
CDs, DVDs and their subgroups (CD-R, CD-RW, DVD-R, DVD-RW) all look identical but are not compatible. How do drives and players identify them? asks D. Smyth of Bracebridge, Ont.
"When my morning toast pops out of the toaster," says Des Writer of Halifax, "it's not too hot to handle. Contrast that with bagels and hot-cross buns, which burn the fingers. What's the explanation?
What exactly is UV protection and how is it embedded in the lenses of plastic sunglasses? asks Dolna Garbary of Antigonish, N.S.
Why does a person's accent seem to disappear when they sing? asks John Barker of Sarnia, Ont. "For instance, the Beatles, Van Morrison, Elton John — they all have distinctive accents, but when they sing they sound just like Canadians."
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