If she missed, she wouldn’t get a second shot.

I said, ‘Take it easy.’ Just to be making sounds. Her finger was bone-white on the trigger, but she hadn’t moved it yet. The Speed-Six is a double-action revolver, which means that the first half of the trigger’s pull moves the hammer back and rotates the cylinder. The second half drops the hammer and fires the gun. Complex mechanics, which take time. Not much, but some. I stared at her finger. Sensed the guy with the ballplayer’s eyes, watching. I guessed my back was blocking the view from farther up the car.

I said, ‘You’ve got no beef with me, lady. You don’t even know me. Put the gun down and talk.’

She didn’t reply. Maybe something passed across her face, but I wasn’t watching her face. I was watching her finger. It was the only part of her that interested me. And I was concentrating on the vibrations coming up through the floor. Waiting for the car to stop. My crazy fellow passenger had told me that the R142As weigh thirty-five tons each. They can do sixty-two miles an hour. Therefore their brakes are very powerful, too powerful for finesse at low speeds. No feathering is possible. They clamp and jerk and grind. Trains often skid the last yard on locked wheels. Hence the characteristic yelp as they stop.

I figured the same would apply even after our slow crawl. Maybe more so, relatively speaking. The gun was essentially a weight on the end of a pendulum. A long thin arm, two pounds of steel. When the brakes bit down, momentum would carry the gun onward. Uptown. Newton ’s Law of Motion. I was ready to fight my own momentum and push off the bars the other way and jump downtown. If the gun jerked just five inches north and I jerked just five inches south I would be in the clear.