NPC Mason history

Discussion of specific prototype locomotives and other equipment of all gauges.
Randy Hees
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NPC Mason history

Post by Randy Hees » Sun Jun 13, 2010 8:47 am

Do we know when NPC no 2 (San Rafael/Jack Rabbit) received its first replacement cab?

Bruce published a photo of the engine in Birth (p 216) showing it with the original cab and a intertwined letter NPC monogram. I am trying to date the photo...
Randy Hees

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CraigH
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Re: NPC Mason history

Post by CraigH » Sun Jun 13, 2010 3:55 pm

Randy,

I don't think anyone has gotten around to looking into #2's history. The usual drill, so many open ended items to dig into!

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Re: NPC Mason history

Post by CraigH » Fri Jun 18, 2010 1:42 pm

The Iron Horse 1:29 site as several scans from the usual book sources of San Rafael:
http://www.ironhorse129.com/Projects/En ... Engine.htm

As usual, date are suspect. Three cab styles are illustrated, original Mason Cab, the first replacement, and the post 1905 Point Reyes fire steel cab.

Interesting to note other parts replacements over time:
Headlight and light shelf plus the brace were changed to what looks like a Baldwin stand (maybe when the original cab was replaced?) Also, during the 2nd cab stage, the whole light stand gets removed and the light mounted to the smoke box top.

The whistle and bell stand were replaced as late as the 1905 fire rebuild, possibly earlier. Need to look for some dated images.

There's the usual assortment of smokestack and plumbing changes over time. As I recall, the original smokestack may have been identical to Bully Boy's. IF that's the case, any image we have of San Rafael will postdate the first stack replacement.

What was the lifespan of a smokestack?

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James
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Re: NPC Mason history

Post by James » Sun Jun 27, 2010 5:44 am

Speaking of Mason bogies, is there online data with detailed weights and axle loads for Mason locomotives? The information my own searches have turned up tends to be either too generic or too suspect. The Masterclass '01 image site lists some general weight information on Masons, but the figures are incomplete and vague.

What weight info I've seen points to rather overweight and underpowered locomotives. Hence my desire to see more information. High weight may partly explain the type's reputation as hard on track. The worst offender here is doubtlessly NPC's canceled 0-6-6 #3. If it actually was a 15x20 cylinder locomotive, that'd suggest an axle load of about 8 tons at the bare minimum, and probably more like 9 tons. That immediately explains why the NPC refused delivery (it'd probably have destroyed the NPC's 35 pound rail) but begs the question of why it was ordered at all.

Rich Schiffman
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Re: NPC Mason history

Post by Rich Schiffman » Tue Jun 29, 2010 8:17 am

James,

Please try the following web site with NPC engines listed: http://www.ironhorse129.com/prototype/M ... _Bogie.htm

Good luck,

Rich Schiffman

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Re: NPC Mason history

Post by James » Wed Jun 30, 2010 5:39 am

Thanks for the link. Unfortunately, that's the Masterclass '02 (not '01, oops) image site I mentioned having found previously. I consider the weight listings on that site slightly suspect because the Mason works wasn't known for building 'bad' locomotives--quite the opposite. Case in point, perhaps, the specifications of the standard-gauge 0-6-6 provided on that site fall nicely in line for heating surface, tractive power, and axle load. By the standards of its day, it's a well-balanced design for a freight road engine.

Problem is, the weights listed for the narrow gauge engines aren't so nice. That site lists the weight on drivers for the South Park 'light' 2-6-6T's (the same basic design as NPC 8) as something over 43000 pounds. That seems suspect to me, since it's excessive for a road engine making ~8000 pounds tractive power and seems more like what I'd expect for a switcher. (For example, NPC 2-6-0 #13 had about 42000 pounds on the drivers and developed just under 10,000 pounds tractive power). I've seen no information for heating surface for this locomotive class, except for boiler diameter, which is rather small, though the tubes could easily be long. I'll take whatever data is available! Maybe Mason's 'weight on drivers' listing really means 'weight on front bogie'? That could make a significant difference.

Sadly, that site, nor any other I've found on the 'net, lists any useful weight info for the 0-4-4's. The Smithsonian lists the weight of a prototype 0-4-4 as 18 tons, but makes no mention of whether that's short or long tons (I assume short), loaded or empty, or what proportion of that is on the drivers. NPC #2 had a reputation for accelerating faster than the 4-4-0's could, which suggests a higher weight on drivers, but that's mere conjecture. Considering that the 8-18C's were already overweight for 35 pound rail, even higher weight than that on a hard-riding design couldn't have been a good thing. At the very least, it's no wonder the NPC mostly ran its masons at low speeds. An overweight, hard-riding locomotive isn't going to be kind to the rails. The 4-4-0's, at least, ran smoothly and curved easily.

*notably, the familar 8-18C plan 4 is also on the heavy side for the tractive effort it makes, which, combined with its high boiler capacity by the standards of the day, explains why most of them had 12x18 cylinders from mid-1876 onward. Notably, the initial 13x16 Moguls such as "Glenbrook" used basically the same boiler, too, and *still* ran fine at normal narrow gauge speeds, albeit with a very long fixed wheelbase.

The NPC seemed willing enough to run locomotives on lighter rail than was advised. What weight of rail was the South Park laid with?

The tantalizingly incomplete info I've found and discussed above leaves me with more questions than answers.

dsp&p_fan
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Re: NPC Mason history

Post by dsp&p_fan » Wed Jun 30, 2010 8:15 am

43,000 pounds on the drivers doesn't seem that bad for 35# rail. The South Park had 35# rail and also ran huge 2-6-0s and normal sized 2-8-0s over it. Herman Darr has told me that the NCNG ran their massive #9 over 35# rail without a problem (I found that shocking). I tend to suspect that the 35# rail in these cases didn't last too long.

Hol Wagner has some nice info covering the last of the South Park Mason Bogie in service (C&S #1, ex-Buena Vista):
Weight on Drivers: 39,000#
Weight on trucks: 6,000#
Tractive Effort: 10,806#
FoA: 3.6

According to Poor, this engine had a WoD of 45,000# and the South Park Masons varied from 42,000#-55,340#. Since the lead truck was a retrofit in some cases, I don't find it surprising that this detail would be confusing.

Additional info from Wagner:
Grate area: 12.5 sq ft
111 2" flues
A total heating surface of 650.3 sq ft
Boiler Pressure: 150 psi

By comparison, the rebuilt Cooke 2-6-0s:
Grate area: 14.7 sq ft
196 2" flues
941 sq ft total heating surface
BP: 190psi
WoD: 64,000
TE: 16,351
FoA: 3.91

I'd expect that, based off of their grate area and heating surface (relative to BP and TE), they'd reach their peak horsepower at a high speed for narrow gauge power. Their reputation on the South Park was to steam really well and be able to flat out fly despite their 37" drivers. The low weight and tractive effort were likely a problem, along with the FoA, on the 4% grades and 20 degree curves of the South Park.

I tend to recall that it wasn't that the NPC rejected Tomales, but rather that it was too heavy for the SG railroads to deliver it (a decent chance that she would have been too heavy for the NPC). 15"x20" cylinders seems reasonable to me: The 2-8-6ts on the South Park had 15"x20"s.

As to dating photos, I wish it was easier to find out why authors date certain photos the way they do. I'd have a far easier time trusting captions if they gave explanations.

Michael

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Re: NPC Mason history

Post by James » Wed Jun 30, 2010 10:29 am

That's some great info there, thanks. There was some of precisely the sort of info I was looking for, exactly why I like this site :)

"15"x20" cylinders seems reasonable to me: The 2-8-6ts on the South Park had 15"x20"s"

Of course, the South Park machines carried their weight on an extra set of drivers, plus whatever the pony truck carried.

I especially like the weight listings you provide for the 2-6-6 (thank you!); it corresponds nicely to my suspicion that listed weights on some other sources may be listing the entirety of the weight on the lead bogie as weight on the drivers--or, perhaps, listing weights after modifications and whatnot (I'm interested solely in as-built conditions). 45000 pounds on the drivers is high for 35 pound iron rail; that 6000 makes a crucial difference because lowering axle load to 39000, while still slightly on the high side for that rail, is vastly more manageable (axle load reduced by a ton!). It also puts the weight more sensibly in line for the tractive power those engines would have had.

In short, those numbers make it look like a well-designed, balanced machine, and not the underpowered pigs some other sources make them out to be. Of course weights will gradually change over the years with rebuilds, added equipment, etc., so must always be understood with that reality in mind.

I also appreciate info relating to heating surface, etc. You're right, that's quite a massive grate area for a NG engine of that size, especially one that I suppose also had a deep firebox. How long were those flues? Also, was that for the 42 inch boiler version ('heavy' 2-6-6) or the 38 inch boiler model? The weights and number of flues make it look like it's the larger variant, but I'm no expert on Masons (though I may become one if I ever find all the data I want!).

I believe--correct me if I'm wrong--NPC 8 was a 38 inch boiler locomotive with 13 inch cylinders. If the weights listed above are indeed for the 42 inch boiler model, do you have specifications for the lighter engines as well? As I understand, the lighter South Park Masons were effectively the same design as NPC 8, except in having the pony truck fitted. Again, correct me if I'm mistaken in that impression.

---------------------------- (slightly off topic part)----------------------

I suppose I should quantify my use of the word, 'overweight', since that word carries some negative connotations. Perhaps it's enough of a loaded term that I should avoid using it (opinions welcome!).

I consider an engine 'overweight' for a given rail size once it starts to exceed the weight that locomotive builders suggested. Rails can and did support more than such recommendations; recommended weights weren't the most the rail could support, but rather that which was deemed prudent in the interest of running without subjecting the line to undue wear and tear. For 6- or 8-coupled locos intended to run at speed on 35 pound iron rail, Baldwin, Brooks, and Porter all suggested axle loads of not much over 11,000 pounds. Heavier locomotives could be used provided speeds were reduced, but increasing weight means more wear and tear and more frequent replacement of rails. Weight can only be increased so much before the rail can't support it anymore and the line starts experiencing lots of broken rails and such.

The general consensus during the 1870's between various engineers, ironworks, and locomotive builders seemed to be that the maximum safe carrying capacity of the average iron rail was about 1 long ton per 10 pounds of rail/yard, or something in the vicinity of a 16000 pound axle load for 35 pound track--at very slow speed. 11000, 14000, even 15000+ is therefore all workable, but at ever decreasing speed and higher wear/accident risk as weights increase.

That's for iron rails, the de facto standard during the 1870's. Steel rails were already appearing by then and are, of course, superior. By the time NCNG #9 wound up on that road in the early 30's, I figure the road long since would have been tracked with steel rail, and #9's weight was such that it could run on steel track of that weight, albeit being on the upper end of the permissible range.

As for the South Park engines...the initial 2-8-0's, as you know, were Baldwin 10-24E's which would have been a little heavy, but not *too* bad, for 35 pound iron rail. The later Cooke Moguls, though (and I presume the Brooks engines), seem impossibly heavy for 35 pound iron rail at the weights you list. Had the South Park re-tracked with steel rails by the time those locomotives arrived on-scene in the early 1880's?

dsp&p_fan
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Re: NPC Mason history

Post by dsp&p_fan » Wed Jun 30, 2010 10:56 am

I don't believe they'd replaced the rail at that point, but I'm far from certain. I don't recall when steel rail began to supplant iron rail, but the South Park was built to very high standards for a narrow gauge. Perhaps the post-Morrison construction included steel rail. I can't recall either, what the tie spacing was (which is a component in how much weight the rail could support). The bogies didn't rotate as smoothly as expected (the reason that lead trucks were added), but they were deluxe locomotives. Personally, I tend to think that running them backwards like a true Forney might have been a better alternative to a lead truck...but I'm no expert either.

The numbers are from one of the "heavy" mogul bogies. Flues were 9'11" long.

I'd probably use the phrase "a bit heavy for" rather than "overweight".

I don't recall how close Bully Boy was to the DSP&P engines. My interest in the NPC is more focused on Kimball cars being pulled by 8-18Cs...and definitely more of a listener than a talker with that road.

Michael

James
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Re: NPC Mason history

Post by James » Wed Jun 30, 2010 12:42 pm

Was that Mason built with the 150 PSI boiler? I've been operating on the assumption that the Masons used the generic 125-135 PSI which was typical for the iron-boiler era 1870's. Certainly the early Mason Bogies (the NPC engines, the centennial engine, etc) are listed as though using 130 pound boiler pressure.

(Edit) Hmm, what was that firebox, 50 x 36 or thereabout? That'd give about a 12.5 square foot grate area, had to be somewhere in that vicinity. If that's the case, I'd expect the depth to be somewhere around 54 inches or so, give or take a couple inches (not having the specs it's just a best guess on my part). Proportionally, that's about the same as the familiar 8-18C d4 which we all know (a tiny fraction worse, or better, depending on whether you're talking about a 16- or 18-inch stroke 18C), just scaled up for that much more tractive effort. Oddly, the boiler tube area was NOT scaled up nearly as much, having only around ~17% more tube surface...probably due to the need to stay within target weight goals. What an odd locomotive design (maybe that's why I find them intriguing).

Heh, I think some of the other folks posting on this site may well understand how there's just never enough information, there's always some piece of data missing!


I doubt running the Masons in reverse would have helped the ride since both bogies could pivot (ie, there was no way for the tender truck to 'pull' the driving wheels into a curve). I believe the pony trucks were connected directly to the driving wheels' subframe as a remedy to that issue.

One still has to wonder why the NPC ordered a locomotive (orginal #3) that was probably too heavy for their line. Perhaps someone made a mistake in the ordering process? Guess that one's lost to history.

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