Execution Expired when running a script


I have a “script” that loads a Rails app by loading config/environment
and then runs… well, forever. Eventually, this script gets an
“execution expired” from timeout.rb, and apparently (from Googling) this
is because there is some maximum execution time limit set in Ruby or
Rails or something. How do I go about changing (removing) this limit? Is
there in fact, no such limit, and I have a different problem?