The GP-9 has a ... I'll say "coil" ... of pipe on the roof of the long hood: two side-by-side lengths of ... 3-inch? ... pipe, connected by a U-bend at one end. Similarly, the F-9 has a coil of this sort on its roof, which is not there on the F-7 or... well, there are no "F-18" to compare. (The second order of FL-9 for the New Haven have the 1800 horsepower engine of the contemporary GP-18, and so could have been called the FL-18. I don't know whether the two orders differ in regard to roof-top piping.)
QUESTION 1: I've assumed that this pipe was a cooling radiator for the air compressor. Is this right?
Today, on the display layout of the Edmonton Train Collectors Association (Bonnie Doon Shopping Mall, Edmonton AB), I saw an O-gauge Union Pacific passenger train pulled by an A-B set of ... well, E-8 or E-9. These units had (molded in the plastic of their roofs) what looked like similar pipe coils: one on either side of the rearward set of radiator fans.
QUESTION 2: Are these in fact the same sort of appliance as the GP-9 and F-9 rooftop pipe coils?
QUESTION 3: The E-8 being of the same generation as the F-7 and GP-7 and the E-9 being of the GP-9 and F-9 generation, is the presence of these pipes a sign of an E-9 (a spotting feature if you ever see one in overhead view)?
QUESTION 1: I've assumed that this pipe was a cooling radiator for the air compressor. Is this right?
Today, on the display layout of the Edmonton Train Collectors Association (Bonnie Doon Shopping Mall, Edmonton AB), I saw an O-gauge Union Pacific passenger train pulled by an A-B set of ... well, E-8 or E-9. These units had (molded in the plastic of their roofs) what looked like similar pipe coils: one on either side of the rearward set of radiator fans.
QUESTION 2: Are these in fact the same sort of appliance as the GP-9 and F-9 rooftop pipe coils?
QUESTION 3: The E-8 being of the same generation as the F-7 and GP-7 and the E-9 being of the GP-9 and F-9 generation, is the presence of these pipes a sign of an E-9 (a spotting feature if you ever see one in overhead view)?