It's Curious City, where we take your questions about Chicago and the region, and investigate, report, explore, from WBEZ.

Hi, I'm reporter Sean Kennedy.

This time on Curious City, we've got a question you've probably wondered.

It's from R.C. Jones.

What determines the route of CTA-L-Train lines?

Some of them seem to zigzag for no apparent reason.

RC commutes every day on the Brown Line, which stair steps from the loop to the northwest side.

If you're not sitting down and holding on, you could definitely fall over with all of the

turns back and forth.

If you're reading a newspaper or texting, you're going to eat it.

This is so.

Think about the L-map for a second and how the lines twist and turn and jog.

You'd think nice, straight lines would make more sense, right?

Faster, more efficient?

After all, three quarters of a million people commute on L trains each day,

and you'd think they'd want, nay, demand, the fastest route possible.

But it doesn't work that way.

So we're going to learn how train lines got their kinks and hear some backstories.

By the time we hit the end of the line, this will make sense for RC and hopefully you.

Thank you for riding the CTA red line.

We'll start with general patterns.

I spoke to Graham Garfield, who both works for CTA and is a transit historian.

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