[tz] switches at 1883-11-18 at the same instant

[Michael H Deckers]

    On 2018-03-19 09:18, Glenn A. Walsh wrote in a post
    to a different mailing list:

> Centennial: Official Enactment of U.S. Time Zones & Daylight Saving Time
> A century ago today (March 19), U.S.President Woodrow Wilson signed into law the Standard Time Act of1918, which officially established time zones in the United States aswell as Daylight Saving Time. Although time zones had beenunofficially observed for a few decades.
> MORE INFO - CLICK ON IMAGE OR LINK --- LIKE THIS POST? - PLEASE SHARE!
> Link >>> http://spacewatchtower.blogspot.com/2018/03/centennial-official-enactment-of-us.html
>


   The link describes (among many other things) how the Allegheny 
Observatory
   synchronized the switch of US railway times to grid time zones. As 
one would
   expect, the switch was done at a single instant, when UT was 
1883-11-18 + 18 h.
   This differs from the current description in tzdb which uses 
different instants
   for different target time zones -- not a likely choice for 
simplifying a nationwide
   railway schedule. Thus I propose:

    - Zone America/Los_Angeles -7:52:58 -     LMT     1883 Nov 18 12:07:02
    + Zone America/Los_Angeles -7:52:58 -     LMT     1883 Nov 18 10:07:02

    - Zone America/Boise      -7:44:49 -      LMT     1883 Nov 18 12:15:11
    + Zone America/Boise      -7:44:49 -      LMT     1883 Nov 18 10:15:11

    - Zone America/Phoenix    -7:28:18 -      LMT     1883 Nov 18 11:31:42
    + Zone America/Phoenix    -7:28:18 -      LMT     1883 Nov 18 10:31:42

    - Zone America/Denver     -6:59:56 -      LMT     1883 Nov 18 12:00:04
    + Zone America/Denver     -6:59:56 -      LMT     1883 Nov 18 11:00:04

    - Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53
    + Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 11:12:53

    - Zone America/North_Dakota/New_Salem -6:45:39 - LMT      1883 Nov 
18 12:14:21
    + Zone America/North_Dakota/New_Salem -6:45:39 - LMT      1883 Nov 
18 11:14:21

    - Zone America/North_Dakota/Center -6:45:12 - LMT 1883 Nov 18 12:14:48
    + Zone America/North_Dakota/Center -6:45:12 - LMT 1883 Nov 18 11:14:48

    - Zone America/New_York   -4:56:02 -      LMT     1883 Nov 18 12:03:58
    + Zone America/New_York   -4:56:02 -      LMT     1883 Nov 18 13:03:58

   Michael Deckers.