Building the B&O P-7d “Cincinnatian”
text, drawing and photo by Phil Bonzon, MMR
In 1946, four class P-7 Pacific’s were streamlined at the
B&O Mt. Claire shops for service as P-7d’s on the
Cincinnatian train operating between Baltimore and
Cincinnati. The “Cincinnatian” has been imported as a brass
engine and occasionally one is found for sale, but at prices
beyond my engine budget, so I choose to build one. My steam
locomotive started as a Bachmann Spectrum Penny K-4, 4-6-2
that I modified to closely capture the appearance and
features of the B&O 4-6-2, P-7d (Cincinnatian) number 5301.
The Penny K-4, USRA heavy Pacific and the B&O P-7d were very
similar in size, wheel size and wheel spacing (MR
Cyclopedia-Volume 1, Steam Locomotives, by Linn
Westcott); therefore the K-4 is a good starting point for
modeling the P-7d.
Like the prototype, I started with an existing frame/boiler
and clad over the existing boiler with a new scratchbuilt
streamlined cladding, pilot, smokebox front and cab. First
the engine was disassembled and the Belpaire firebox was
ground off; then that area was covered with a layer of
0.010-styreene sheet; length-wise stringers/running boards
were made from styrene strips; a styrene disc was made and
applied to the smokebox front; all of which served as
guides/supports for the new 0.020-styrene boiler wrap that
was bonded to the ‘stringers’ with plastic solvent cement
and clamped in a vise to hold it shape while drying. The
sand dome was removed, reshaped, rotated 90 degrees and
reinstalled. The air pump was removed from the side of the
boiler because on the B&O it was in the streamlined pilot.
The smokebox front was formed from multiple layers of
styrene sheet discs bonded together, sanded to shape and the
gaps filled with plastic putty and sanded to final shape; a
hole was drilled to accept a styrene tube for the headlight.
Styrene Filler plates were added between the stack and the
domes, also between the domes and the valves. Steps were cut
into to the sides of the boiler cladding with a #11 X-Acto
blade and the gap between the new cladding and the old
boiler were filled with plastic putty.
The cab and side skirts were fabricated from 0.040-styrene
sheet and bonded to together with plastic solvent adhesive.
Holes for handrail stanchions were drilled through the
boiler cladding to accept the stanchions from the Bachmann
The pilot and steps were fabricated from various thickness
of styrene sheet and bonded together with plastic solvent
adhesive. Then sanded smooth to blend together.
The cab roof was made from 0.040-styrene sheet formed to the
curved shaped and bonded to cab sides with plastic solvent
The trim strips and window frames were made from 0.020-brass
wire that I annealed, bent to shape, soldered together and
bonded in place with CA adhesive. All handrails were formed
from 0.020-brass wire. Brass grab irons fabricated and
installed on the boiler. A Cal-Scale brass B&O Capital Plate
was added to the pilot, as were classification light to the
Working from the prototype drawing and photos, I
scratchbuilt the tender body and frame from styrene sheet
and shapes that were bonded together with plastic solvent
adhesive. ½" diameter styrene tubing was slit lengthwise to
form the curved top edge. The curved roof over the recess
was formed from 0.030-styrene sheet.
The top deck of the tender was made from 0.020-styrene sheet
and is removable for access to electronics. The steps,
handrails, ladders, cut lever, brake gear and coal bunker
doors were reused from the Bachmann tender and installed on
the new body. A Kadee coupler was installed and Precision
Scale’s brass Commonwealth six-wheel brass tender trucks
were assembled and installed. Also, Cal Scale’s brass
air-hoses and steam line were installed.
This Bachmann engine did not have DCC or Sound; I discarded
the PC boards and lights, then installed a NCE motor decoder
and MRC sound decoder in the tender, which I hardwired to
the engine. Also, I installed a LED headlight and LED tender
backup light. The tender wheels and the engine drivers
provide electrical pickup.
Finish and Lettering
The engine and tender were primed, using an airbrush,
with Floquil enamel Primer; then Floquil Engine Black was
airbrushed, the black areas masked and then airbrushed with
Floquil Dark Blue. The handrails, trim and window frames
were given a brush coat of silver enamel. The entire
engine/tender were airbrushed with Floquil Clear Gloss
enamel in preparation for decals. The road name,
Cincinnatian signs and numbers, I generated on my computer
and transferred them to decal paper and applied them to the
model. Model Graphics dry transfer silver stripes were
applied. The model was again airbrushed with Floquil Clear
Gloss enamel to protect the decals. The model was then
lightly weathered (using an airbrush, with thinned Floquil
Grimey Black and Grime) since the Cincinnatian was a crack
B&O passenger train and was keep clean with only the grime
and soot accumulated from its daily run..
The engine’s streamlined pilot, boiler, cab, handrails,
trim and window frames are scratchbuilt, and also the tender
body and frame were scratchbuilt. The decals were
scratchbuilt using a computer.
Phil’s model of the B&O P-7d 4-6-2 “Cincinnatian” #5301
won First Place in the “Scratch Built Steam Locomotive” and
the “William J. Lenoir Memorial Award” for Best Scratch
Built Steam Locomotive at the NMRA 75th National Convention
in July 2010. A month before, at the MCoR 2010 Convention,
this engine won First Place in the “Scratch Built Steam
Locomotive” category and “Best of Show” in the merit judging.