Scored the above in kit form. It arrived today and looks quite nice. Coupla
1) Which 4-6-2 is this supposed to represent, or is it a hodge podge of
prototype features? The long ligh fixture on the formt boiler and the absence
of a light at the top thereof say that it's not a PRR K4. The long nose looks
more like a N&W I saw a profile of.
Woule it be just a matter of adjusting those details to move it toward one
company's version or another?
2) It has an open frame motor. Though it unused, still sealed inplastic would
I be better off remotoring right from the start. Yardbird Trains and NWSL
both have motors and Yardbird has some very nice detail sets including a cab
It's a fairly good representation of a USRA light Pacific. As such, it
can be adapted to make a more or less accurate model of a variety of
prototypes. The devil's in the details - there aren't nearly as many
steam loco details available now as there were a couple of decades ago.
However, real hobby shops tend to hold onto old, outdated stock, knowing
that eventually someone will want it, so hie thee to the nearest one and
sniff around. Good hunting!
The mech is barely acceptable by today's standards IMO, but can be
run-in to operate quite smoothly. The weak point is the nylon worm (if
that's the version you have) - nylon doesn't wear in the way metal does.
So if you remotor, also get new gears - if memory serves NSWL makes a
complete motor + gears replacement kit.
Aren't they all? "Davy Cormack feels this model is actually based largely on the B&O P7
class Pacific of 1927, the so-called "President class" since they were
named after the first presidents. Cormack said the 20 locos of P7 class was
very similar, but not identical to the USRA heavy. The cab and tender of
the model don't match, as well as a couple of details on the boiler but the
boiler is 90% correct. He said the model appears to be based on P7 no. 5314
as she was after initial rebuilding in the 1940's, including the use of 80
inch Boxpok drivers. Other P7 locos had a mix of driver types in later
years. Nos. 5314 and 5316, for example, had Boxpok, while others such as
nos. 5309, 5315, and 5312 had standard spoked drivers."
Interesting comments. However, since the Mantua Pacific has been used as
the basis of a reasonable stand-in for the CNR Pacifics, I don't think
"heavy USRA" is correct. Was the B&O President class based on the USRA
design(s)? A lot of engines built the 20s/30s were copies or adaptations
of the USRA designs, or so I've been told. And the USRA designs combined
the most common features and practices of then existing engines, so that
they would be as "universal" as possible.
"Our model is a U.S.R.A. Light Mikado boiler, but we have fitted it to
drives other than the Mikado to give the modeler a wide range of similar
engines for his railroad's roster, with a family look. Our boiler is a
smooth, clean, accurate die casting, fits the Mantua (Tyco) Mikado,
Pacific, or Decapod drives. When ordering, please specify which drive you
intend to use the boiler on, as the drilling for mounting holes is
different. We have provided a drawing for making the running boards out of
thin stock (stock not included), which mount on wires that pass thru the
boiler. A lost wax brass smokebox front is included with the boiler. The
boiler can be ordered completely drilled for mounting the parts in our
Detail Kit #520, which includes basic U.S.R.A. detail parts used on
U.S.R.A. engines as originally built, or the boiler can also be ordered
undrilled, if you wish to arrange things the way you want them. Either way
the holes for mounting the boiler on the drive are drilled and tapped.
Detail Kit #520, which is available separately as well as other U.S.R.A.
parts, is listed elsewhere in this catalog."
(on page 7, just above a picture of one mounted on a Pacific mechanism)
Big heavy hunk of metal:
"I doan gotta show you no steenkeeng traction tires."
Also lots of detail parts:
and Helix Humper can motor and gear kit for the Mantua Pacific:
The B&O P-7 was closely based on the USRA heavy pacific (e.g. Erie K-5, the
only RR to receive USRA heavy pacifics), but was not a direct copy. The P-7
was slightly larger, to wit (read in 3 columns):
Dimension(both as-built, from reprints of the RR diagram booklets)/K-5/P-7
1st boiler course dia./78"/78"
3rd boiler course dia./90"/90"
Length over tube sheets/19'/19'
Loco weight (working)/315,450lbs./326,000lbs.
Measuring my old Mantua pacific, the boiler diameters appear to be about 2
scale inches larger than the above dimensions. But that may be that (I
believe) the diagram books give the diameters of the boiler itself, and not
the boiler with lagging and jacket, in which case the model boiler may be a
couple scale inches under size. Geezer
I used the Mantua as the basis for a B&M P4 kitbash. Turns out the
Mantua model's important dimensions (length, height, boiler diameter)
match the B&M prototype give or take a couple of scale inches. I had
photographs and plans of the P4 and worked from them. The B&M didn't
use Boxpox drivers and so I ordered replacement spoked drivers from
Mantua (they were still in business back then) Calscale had a cast
brass pilot that matched my photographs well, and a front deck air
compressor shield that was close enough. A couple of features didn't
get modeled. The B&M had a nifty teardrop shaped stack and a racy
forward slope to the front of the cab. Both of these details fell into
my "too hard" box, I couldn't think of any way to model them, so I just
ignored them. With a nice paint job and speed lettering decals on the
tender, the result was very nice, and was well received down at the
club. A Boston area club full of knowledgeable old-timers, some of 'em
old enough to have operated a prototype P4.
The stock Mantua drive and motor is very good, smooth, good low speed
running. You won't be unhappy with it. I did a can motor conversion on
mine, and a good mechanism became even better. Stock, the engine would
run down to 4 scale mph. With the can motor, creep speed dropped down
to 0.01 scale mph, it would creep along tie by tie. It runs better than
any brass steamer I ever saw, and just as well as my Bachmann
consolidation. The conversion is easy, just screwdriver work. Was it
me, I'd try for a can motor conversion kit. Yardbird had two of 'em.
Don't remotor until everything is working with stock parts. I
say this particularly as you are just getting back into this. I know
from experience that if you try to do everything perfectly right
away, very often you get bogged down. Therefore, I wouldn't
go pulling axle gears or remotoring just yet. If and
when you do remotor it, you want to have a decent-running
baseline to compare to, with the bugs already worked out.
Furthermore, if you evaluate the performance with the old
drive, you know just what improvement has been made.
Depending on the motor, you may not even want to replace
it. If it's a "Power Drive" version with a covered worm and
chunky MG81 motor (DC71-like appearance, stamped pole
pieces) the noise level and low speed performance shouldn't
be too far below present-day standards, and at any rate
your Mantua's pulling power is going to walk all OVER
present-day standards. If it's a plain angle-mounted
PM-1 (smallish open-frame with cast pole pieces) there's
a stronger case for remotoring, but again, don't remotor
until the engine is running and broken in.
Wolf is right that the nylon worm & gear are a Mantua
weakness; Mantua was a pioneer in the use of plastic in
model railroading, believe it or not. The first Booster design
had a plastic frame...in the early 1950s, but it apparently
was not successful. The plastic gearing was one of their
ideas that worked well enough to keep, but probably
shoudn't have. However, the Helix Humper has a brass
worm, and works with the present axle gear, which does
eliminate the problem of running nylon on nylon. However,
as I said, don't worry about that right away.
As for detail parts, Bowser and Yardbird have a lot.
A lot of steam detail can be made from wire or bits of
brass, too, or scavenged from plastic models as John
Allen was known to do. Again, I wouldn't worry about
that until you've got a good-running engine.
Suggestions for kit assembly:
Mantua kits were very well-engineered, and I find that
most parts fit properly. As with any kits, you should
take your time, and follow the instructions. Remove
flash from parts first, using files and perhaps an Xacto
You may occasionally find flash in the axle-slot
ends. Remove this carefully, but do /not/ file the
inside of the axle slots. On some kits, I have
lightly scraped the /top/ of the slot to ensure all drivers
pressed on the rail evenly, as determined by pushing
the chassis with fingers lightly braking the drivers,
but Mantua has bearing shells located by pegs, so
don't do this. You could perhaps add shims if
needed, but as I said Mantua tended to have good
Riveting the valve-gear together is not easy, but
you've built kits before so you'll pick up the skill.
Just be careful and follow the kit instructions.
Bowser has a riveting tool.
Be sure to adjust the worm-gear mesh, as
recommended in the instructions.
Look at the punched side rods. You will note
a slight rounding on one side, which is the
side that dropped through the die. It is best
if you arrange the rods on both sides so that
this rounded side faces the same way...i.e.
both right or both to the left. This way, any
inaccuracy in the pinhole spacing tends to
Some modelers use Loctite on crankpin
screws. I've never done this, but it sounds
like it could be a good idea. Has anybody
out there tried this? If I did, I'd use a
removable, fairly weak grade.
You will note that the instructions recommend
that you run the mechanism at frequent intervals.
This is important. In fact, the assembled mech
without its motor should coast very freely down
a slight grade, almost like a boxcar. This is
vital to a good-running kit loco of any brand, and
it's one area where RTR manufacturers just can't
afford to match your own efforts. My MDC 2-6-0
runs much better than the locos MR tested,
and it's because I worked every bind out before
going to the next step.
I don't want this to sound discouraging. Kit
building is a blast,and it's not that hard. The only
REALLY hard part is developing the patience
needed to tell yourself "I will complete this step
and this step only, and I will not ruin my work
by rushing". I ruined several kits before I
learned this lesson, and I'd like to save others
the same problem -- but I'm sure you already
learned it with plastic models, of which I probably
ruined a dozen through haste and carelessness
before I got one right...it was a 1957 Chevy, two
tone green. I remember busting a lot of shirt
buttons over that one, and it made up for a lot
of my junkyard (but in retrospect, probably not
for the 1970 MPC Popcorn Wagon kit that I tried
to assemble with Elmer's glue and Seal-All.
Oh, the humanity...)
Of course I promptly made the opposite error,
and decided my next kit would be modified with
you guessed it, it never got assembled. This is the
source of another lesson - get the basics down
thoroughly before attempting embellishments,
and that's largely behind my comments about
remotoring. I've had to learn this lesson many
times, too; I am not by nature a patient person,
but one who tends to rush and get discouraged
quickly, unless I make a conscious effort to
avoid it. Quite frankly, if I can do it, anybody
To be fair, these lessons which I learned at some
cost to my finances and my ego have paid off
very well in other areas. They made me much
more careful when fixing the house and car, or
even at my job, to always find instructions if
possible, to always read the manual or standards,
and to work slowly and carefully when encountering
an unfamiliar system.
By all means, though, don't let me worry you.
Too many people moan and groan about what
they can't do, but never try. Even if you do ruin
some parts, you can order new ones, right?
If you have any questions, just ask.
President, a box of track and a gappy table.
Some 35 years ago I did a conversion of Mantua 4-6-2 based on a CNJ G3
although the Mantua sand domes are wrong for the G3. The boxpox drivers
were replaced with PennLine/Bowser 80" drivers..also Tyco valve gear hanger
and crosshead were replaced. Stock Mantua motor gave way to Pittman open
frame motor although do not recall which one. That motor was balanced and
trued up with the result the loco would move out with 5 AHM passenger cars
in tow at 1.5 volts.
For pix see January 1972 RMC,. paged 50-51.