I think there was a typo in Richard's response.

--- In STMFC@..., Richard Hendrickson <rhendrickson@...>
wrote:

Dalman two-level trucks were widely used in the mid-to-late 1920s,

and

the Dalman one-level truck enjoyed some brief popularity in the early
1920s.

The Dalman one-level truck actually succeeded the two-level design
(which wasn't called a two-level until the introduction of the one-
level).
Production dates for the Dalman one-level truck, that I know of,
covered 1929 to 1931.

Brian Leppert
Tahoe Model Works
Carson City, NV