-------------- Original message --------------
From: Richard Hendrickson <rhendrickson@...>
On Nov 5, 2008, at 8:48 AM, al.kresse wrote:

Do we have the short list of key reasons (such as market and
technology) for the shifting of "standard" NEW and REBUILT steel box
cars becoming 50-ft vs previously 40-ft box cars after WW2 and into
the
fifties? Especially in the midwest and east?

No mystery here. After WW II box car traffic increasingly shifted
toward lighter, bulkier loads, notably auto parts, for which 50' cars
were better suited. This trend was reinforced by the development of
covered hoppers for grain service, replacing the 40' box cars with
grain doors that had formerly been used. And I would take issue with
your "especially in the midwest and east" statement. For example,
the Santa Fe built their last 40' box cars in 1952; all new box cars
delivered after that date were 50' cars. The same decision was made
by the Southern Pacific only a year later, in 1953.
Essentially, by the early 1950s most RRs owned all the 40' box cars
they needed, while much new rail traffic required longer cars with,
in many cases, DF loaders and other special loading equipment.

Richard Hendrickson