In the article as I found it on 4/14/2014, it read the following under the Troop Line for the Galactic Empire:
- "Some, such as the Delta-class troop transport, have been converted from true transports to glorified attack shuttles, but many remain in service as intersystem transports as the Army grows.''"
- ―Imperial Sourcebook (p. 105, 2nd ed. p. 102, 1st ed.)
This was written before the DX-9 made its first appearance in the X-Wing computer game in 1993. The Imperial Sourcebook was first published in 1989, four years earlier. 'Maybe', the computer-game creators took the 'Delta'-class transport name from the Sourcebook and applied it to this little shuttle, but if they did so, they took excessive liberties.
Furthermore, it doesn't seem credible that a troop line would consist of a number of cruiser-size escorts for a couple of small shuttle-scale transports only ferrying some 30 troopers each.
It must be referring to something that was never fully fleshed out in the material. As such, I'm removing the reference, and inserting the original language.
The Far Orbit Project , regrettably, does not flesh this out any further.