Josh, the reality in the US of A is that the law mandates reasonable accommodation of their sincerely held religious beliefs, including precluding work on their day of rest.
The reality is also that both ConEd and the MTA employ a significant number of observant Jews in a broad array of positions that require 24/7 coverage, including bus drivers, train conductors and power plant operators, and permit them not only to take off every Shabbos but to leave early enough to prepare for Shabbos b’kavodik.