GR translation: any least mistake, in the points,

[Monte Davis]

Railroad points (http://en.wikipedia.org/wiki/Railroad_switch)

-----Original Message-----
From: owner-pynchon-l at waste.org [mailto:owner-pynchon-l at waste.org] On Behalf
Of Mike Jing
Sent: Wednesday, July 11, 2012 5:56 AM
To: Pynchon Mailing List
Subject: GR translation: any least mistake, in the points,

P221.37-222.2   They are being pushed backward by a line of police.
Peter Sachsa is jammed inside it, trying to keep his footing, no escape
possible . . . Leni's face moving, restless, against the window of the
Hamburg Flyer, concrete roads, pedestals, industrial towers of the Mark
flying away at over a hundred miles an hour the perfect background, brown,
blurred, any least mistake, in the points, in the roadbed at this speed and
they're done for . . .

What is the meaning of "in the points"?  What points are we talking about
here?