The Rochester & Genesee Valley Railroad Museum has not been able to locate any photographs of any of Plymouth's Model BL locomotives, however, we were able to locate a Plymouth sales catalog showing the Model BL. Here are a few scans from that catalog with lots of detail on the BL and all of its mechanicals.   We have included the full pages along with close ups of the artist renderings of the engine.   Of note, the BL clad in its full sheet metal is actually a narrow-gauge version of the engine with the wheels inset inside the frame vs. outside of the frame like the R&GVRRM's standard gauge BL. 

As always, the R&GVRRM looks to grow its understanding of our BL's history.  Have anything you can share with us?   Please let us know.