What model engine is on the right

@peter allen 072518 posted:

I found this photo on-line and after several hours of searched I was unable to find any reference to a B&O engine with number 988. I am guessing it was a factory number and then was re-numbered at some point? I am trying to figure out what model of engine this is. My best guess is an EMD FT but I would love to know for sure. 

It is definitely NOT an EMC/EMD FT model, as those number boards and class lights are from much later F or E Units.

EMD F7a

Stuart

 F7a if the chart I found was right; it was a block of nunbers vs individual notation.

The steam was a Q w/Vanderbilt in another shot found.

Thank you all for your help. 

All of the B&O steam locomotives numbered in the 4400 series were Q-4's. All except a few (like the one in the photo) had the headlight mounted high on the smokebox front. The high mounted light in the case of 4493 is a red light for reverse movement in helper service. The headlight is centered on the smokebox front.

Locomotives with these red lights were normally used as helpers on the old (original) main line around Mt Airy, MD, and the red light was turned on when backing after cutting off from helper service. These locomotives were put on the rear of the train as helpers.

Original numbers on B&O F7s were in the 100s.  Since this engine is in a different number series it's different in some way.  I recall reading something many years ago about B&O engines assigned at Keyser, WV, having a different gear ratio, 65:12, versus 62:15.  The article was written when B&O was using F7 consists in its mountain grades and there was mention o a special group of F7s that was used on 17 Mile Grade and on Sand Patch.  

The 65:12 gear ratio gave a top speed of only 50 MPH, but allowed the continuous rating speed in Run-8 to be lower, which is useful where high speed is not needed and the locomotive can pull more tonnage on heavy ascending grades.

62:15, which was the almost universal standard for F7 freight units, allowed a maximum speed of 65 MPH (and that would include the B&O F7 units numbered in the 100s), but the continuous rating speed was higher.  This would result in the tonnage rating for a 62:15 locomotive to be lower, and we all know that tonnage and freight charges parallel each other.

Bob, you're the ranking B&O expert here, what do you think?  Is my aging memory playing tricks on me?