These are 1.44M disk images.  You need Teledisk to recreate the disks.
Teledisk can be found at:

    ftp://tvdog.shacknet.nu/tandy1000/system/teled212.zip

The disks should be labelled:

Msdos1.td0      MS-DOS 5.0 disk 1 - Startup, Utilities, & Installation
Msdos2.td0      MS-DOS 5.0 disk 2

This is DOS for the 1000RLX and RLX-HD ("B" versions), models 25-1452B
and 25-1453B.  It is unlikely to be useful on other models.
