Downhill all the way

(Apologies for the gap--things at home have been interesting. I'll try to fill in next week...)

The weather has been beautiful today. Blue skies, dry roads. Passing through Nashville on the Interstates, you'd never suspect all the flooding.

The flooding's there, apparently. My mother-in-law lives 20 or 30 miles east of here. One of her neighbors had a wheelbarrow float into his barnyard. My father lives about another hour or two east of her. He spent the night with my brother because he couldn't get to his house without a boat.* But apparently the Interstates are on high ground. I haven't even been inconvenienced.

Under the circumstances I would feel silly complaining about much of anything. So I'll just toss off the most exciting thing that happened today.

Between Nashville and Chattanooga I had my first real taste of the good old days of trucking. Monteagle. Three or four miles of 6% grade. With no engine brake.

I've discussed jake brakes before. And I may have mentioned how much easier they make mountain driving.** But much of that was theoretical. My training included a few steep downhills, but no mountains. And in two years with this company, I've always had the engine brakes working when I was way up there. Being scared on a long downhill was something that happened to other truckers.

That is no longer the case.

Here's a point I may not have made clear before. You've probably taken a car down a steep grade before. A bit interesting, perhaps, but not that scary. Then again, stopping at a red light isn't all that scary for you either. Just take your foot off the gas and you start to slow down.

That's because of the way a gasoline engine works. Your accelerator doesn't just control how much fuel gets into the cylinders--it controls how much air gets in, too. Take your foot off the gas, and all of a sudden the engine is trying to breathe through a straw. Which means turning the engine becomes hard work.

Well, a diesel engine (for reasons that would take a while to explain) never restricts the air coming into the cylinders. When you let off the accelerator, all you cut off is the fuel. Slowing down in a diesel truck isn't quite like coasting, but it's close.

The various engine brake systems basically try to make a diesel pretend it's a gas engine. One way or another, they make the engine work at moving air in and out. Work, as in "use up energy." Energy that would otherwise speed the truck up.

If you don't have a working engine brake, a 77,000-pound tractor-trailer on a 5-6% downhill slope 4 miles long is scarier than I thought it was.

I took the slope at about half the speed I usually do. I was careful with the (regular) brakes, using the techniques they taught me back in CDL school to keep them from overheating. And still I could smell overheated linings. And I had to stop twice because I'd used up all the air in my air brake system.

This was not fun.

But I got down. And I made it the rest of the way to Atlanta. And now I'm at home, feeling dreadfully pleased to be alive.

My fellow truckers are unimpressed. A few more trips like and I might be too. Not yet, though...
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*The house was ok--there just wasn't a road from him to his house...

**Oh, yeah. I did.