The big 2500 hp centrecabs that Lima built for the PRR have come up in the course of a discussion on the EMD forum (string: "EMD field loop dynamic brake control")
More information would be nice.
Background: The Lima transfer units came in at least two variants. One variant had dynamic brakes. We'd like to know what sort of control (field loop or potential wire) the dynamic brakes had on the units with them.
Preliminary questions.
---PRR had two subclasses for the Limas, LS25 and LS25m. I think the db-equipped ones were LS25m.
Q. Did all LS25m have dynamic brakes?
Q. Which units were which? I think I've found a source that says the LS25 and LS25m were in two different number blocks, but confirmation would be nice.
(Kirkland's book on F-M and Lima diesel locomotives says that two units from the PRR's second order of Lima units had db, but doesn't say anything about the first order.)
But the main question is about the control system: the discussion on the EMD forum centres on the history of the different systems used by several locomotive builders.
(Also posted to BLH forum.)
More information would be nice.
Background: The Lima transfer units came in at least two variants. One variant had dynamic brakes. We'd like to know what sort of control (field loop or potential wire) the dynamic brakes had on the units with them.
Preliminary questions.
---PRR had two subclasses for the Limas, LS25 and LS25m. I think the db-equipped ones were LS25m.
Q. Did all LS25m have dynamic brakes?
Q. Which units were which? I think I've found a source that says the LS25 and LS25m were in two different number blocks, but confirmation would be nice.
(Kirkland's book on F-M and Lima diesel locomotives says that two units from the PRR's second order of Lima units had db, but doesn't say anything about the first order.)
But the main question is about the control system: the discussion on the EMD forum centres on the history of the different systems used by several locomotive builders.
(Also posted to BLH forum.)
