Grassroots Railroad Sports?

Here's an easy one for you Nick:

Can you explain Duplex engines a bit? (I am guessing you likely have already in this thread somewhere)  I know they are effectively two engines in one, non-articulating.  I am guessing the non-articulating part is because they needed to share the same boiler (for simplicity?). They were made, I believe, primarily just for more power.  I am also guessing the diesel electrics and their additional, more compact, power, is what made them unnecessary eventually.  Of course they still run more than one engine a lot. The duplexes of course had issues with being too big (long).

It looks like 270 above is a duplex of sorts, but articulated?

In reply to aircooled :

Okay, so the articulated steam locomotive was the answer to needing more driven wheels but not being able to handle a longer rigid wheelbase. Once you get above 4 axles, things start getting dicey as far as curves, and 5 driven axles had some inherent balancing issues as well. An articulated steam locomotive allowed you to have 6 or 8 driven axles but in a much more flexible package. Instead of a 2-12-2 or 2-16-2 that would straighten every curve they encountered, you built a 2-6-6-2 or a 2-8-8-2 that's much more flexible. They used a one-piece rigid boiler (except for some weird attempts at flexible boilers that failed miserably) and firebox that was rigidly-mounted to the rear set of cylinders and drive wheels. The front frame with the leading set of cylinders and drive wheels pivoted both horizontally and vertically under the boiler. If you see a head-on view of an articulated steam locomotive on a curve, you can see how the front half pivots out from under the boiler.

A Duplex steam locomotive was a kind of weird evolutionary dead end. As you added more driven axles, you needed longer rods to connect all the drivers, and as the power of piston thrusts increased, you needed stronger rods. That all added up to heavier rods and heavier reciprocating mass and then larger counterweights to try and counteract it all, and as speed increased, you got these huge hammer blow forces as the rods went around that beat the daylights out of the rails. As the rods came to TDC they would literally skip the drive wheels off the rails, and then slam back down when it came to BDC. You would also get a hunting oscillation, where when viewed from in front the engine would kind of shimmy side-to-side. Baldwin Locomotive Works and Pennsylvania Railroad had the idea of splitting the drive wheels in half, so that you had shorter rods. So instead of a single set of 4 axles with long rods, you had two sets of 2 axles with shorter lighter rods. Since it was still a relatively short wheelbase, there was no need to articulate it. So PRR's answer to a 4-8-4 was a 4-4-4-4 Duplex, and their idea for a high-speed 10-coupled freight locomotive was a 4-4-6-4 instead of a 4-10-4. The PRR Duplexes had some other issues that prevented them from being a success that weren't a fundamental flaw of the Duplex, but by the time they rolled out, there were already two solutions to the hammer blow issue. One was better attention to balance, lightweight materials for connecting rods, and better drive wheels design, all of which was cheaper than the more complex frame and added cylinders and valve gear of a Duplex. The other was the diesel, which had no such issues at all, amongst other advantages.

R&N #270 and #275 are just an EMD diesel called an F-unit. There were a bunch of submodels for variants (FT, F3, F7, F9) and they came in A-units, which had the bulldog nose and cab, and B-units, which had no nose or cab. They were a building block principle. If you needed 3000hp, you ran an A-B or A-A set, for 4500hp, you hooked up an A-B-A set, for 6000hp you ran an A-B-B-A set. At the time, EMD's best engines made only 1500hp from a single V16, so a single 1500hp machine was as good as it got. They could have made a single 3000hp locomotive with twin V16s onboard but it would have been so big and heavy and expensive that only the biggest railroads would have bought them. The B-unit was mostly a cost-saving measure. If you weren't going to strictly dispatch F-units in single unit sets, then you would be paying for all these locomotives with cabs and control stands (and those curved bulldog noses were difficult and expensive to fabricate) that wouldn't be seeing use.

CNJ #113 accelerating to about 25mph. You can see how, without a lead and trailing truck to stabilize it, she gets bouncing the crew around in the cab pretty good. Also, with just 51" drivers, she accelerated pretty quick.

Interesting, thanks.   Yes, bigger seems like a good idea many times until you get into the unintended side-effects.  Lot's of powerful dynamics going on with those giant machines.

In reply to aircooled :

And remember, it was all being designed with slide rules and pencil and paper and a certain amount of trial and error. When it was a new design, there was frequently a period after delivery of the first couple locomotives where the railroads would be in contact with the builder and would give feedback for the remaining locomotives being constructed.

The dynamic augment issues were typically a more prominent issue on passenger locomotives due to the higher speeds and the schedules demanded. A freight engine that had balancing issues could just be restricted to slower speeds. A passenger engine that couldn't keep schedule was just worthless. New Haven took delivery of ten 4-6-4s from Baldwin in 1937 that had some horrible high-speed imbalance issues that took revisions from Baldwin to fix (removing some of the counterweighting was a big part of the solution) Atlantic Coast Line also had some beautiful 4-8-4s, also built by Baldwin in 1937, that were bouncing the drivers off the rails at high speeds and kinking lots of rails. Baldwin tinkered with the counterbalancing and fixed it, and then tried selling ACL some streamlined 4-4-4-4 Duplexes based on what they learned, but ACL went all in on diesels. Baldwin then took the Duplex concept and sold Pennsylvania Railroad on it.

That's not to say that freight engines were entirely immune to the issue. Even if speeds were restricted, you had engineers that would ignore those restrictions, and when an engine went into wheelslip they could also exceed those speeds and beat the daylights out of rails. The Western Maryland had some monster 2-10-0s that were bad about that, and there was an account of a higher who got one of the I-2 2-10-0s into a slip and didn't close the throttle and bent thirteen pieces of rail. Reading Railroad also had some huge 2-10-2s that were prone to the same issue and resulted in a pissing match between the WM and the Reading. The Reading's K-1sa 2-10-2s were running over WM rails on trackage rights and WM track crews got sick of fixing rails, so the WM banned the K-1sas from their tracks. The Reading then responded that WM's I-2s were doing the same to their rails, and responded by banning them. Both railroads came to the conclusion that they'd rather keep fixing rails than lose the business the trackage rights granted and they relented.

Those New York, New Haven & Hartford I-5 "Shore Liner" 4-6-4s were seriously gorgeous machines. New Haven steam power never seemed to get much attention, the electrics and later flashy McGinnis livery diesels stealing most of the thunder. The I-5s were probably the most-photographed of New Haven steam power, and for good reason. They had a bullet-nosed shroud, disc drivers, and black paint with stainless-steel trim and white lettering and striping. They were also quite state of the art with cast one-piece frames, roller bearings everywhere, 285psi boilers, and 80" drivers. Sadly, the more stop-and-go nature of New Haven's lines and various speed restrictions meant that their latent potential was never fully realized. Still, they successfully held off the first wave of dieselization. The Alco DL-109s, with their twin 539Ts and generators, were found to accelerate too slow to keep schedule on the top trains, and do the I-5s were left on those assignments. It wasn't until the arrival of the Alco PA-1s, which made the same power as a DL-109 from a single engine and as a result weighed much less, that the I-5s were retired.

The I-4 class Pacifics that predated the I-5 Shore Liners were a bit more aesthetically questionable. They had an oddly stubby tender (like due to the New Haven's shorter runs), both air pumps under the fireman's running board, and the two air reservoirs were atop the boiler behind the smoke stack with a spoiler of sorts in front of them.

I'd buy a few

In reply to NickD :

I just wish they'd added a dash of creosote to it. 

In reply to Pete Gossett (Forum Supporter) :

Yeah, it's not complete with creosote.

Coal smoke is one of those smells that I'm really going to miss, as more and more steam locomotives are being converted to oil-fired. 

FMW Solutions has published photos of the new, redesigned firebox coming together on PRR K4s #1361. This will be the fix that makes PRR #1361 legal to operate under new FRA regulations. A combination of a flawed PRR design and new regulations from the FRA, along with oversight and mistakes from the previous group restoring it, was what brought the previous restoration to a screeching halt. There's still quite a bit of time before she's going to be up and running though, because it still needs work performed to the running gear and there is the process of converting it to roller bearings on the axle (using a Timken blueprint from the 1930s!). According to Kelly Anderson, Strasnurg Rail Road had just been hired to see about overhauling the side rods and making new shoes & wedges when the oversight committed regarding the roof sheet came home to roost in 2007, and all work stopped.

Rogers Pass 1880s, before the Connaught Tunnel was built in 1916.

So what happened with the PRR boilers that made them run afoul of modern FRA regulations? First, a quick primer on firebox construction and ICC/FRA rules.

Below are cross-sectional views of a firebox and boiler. The upper one is a conventional radial-stay firebox, while the lower one is the Belpaire boiler that PRR and Great Northern used heavily. The outermost portion is the boiler shell, although the boiler shell segment that covers the firebox is typically called a firebox wrapper. The inner rectangular area with the circles is the firebox itself and the circles are the flues.  The top sheet of the firebox is the crown sheet. The arch in the middle of the firebox, labeled BA, is the brick arch, which directs heat, flames, and smoke back over the fire towards the rear of the firebox. Those long lines attaching the firebox sheets and the firebox wrapper are your staybolts. The firebox sheets get very hot and the boiler is under pressure, and so if you didn't have the stay bolts, the firebox would want to collapse in from the boiler pressure. The staybolts also have to be flexible to handle the expanding and contracting forces at work. They are typically installed from the outside, then threaded into and through the firebox sheets, and then the ends protruding into the firebox are peened over to seal them.

On a conventional radial-stay firebox, you can see how, because it's a rectangular firebox in a round boiler, you end up with all sorts of different length staybolts splayed out at all sorts of angles to make it work. The Belpaire boiler on the other hand has the firebox wrapper shaped to match the firebox. This provided greater surface area, although how much of an advantage that was is debated, but also, because the firebox wrapper is parallel to the firebox, there's much more uniform length to the staybolts and they are all installed parallel to the sheets. The downside of the Belpaire boiler was that it was heavier because you had to use a thicker firebox wrapper to make up for the loss of strength in the flat sheets, and it was also more expensive to manufacture and more difficult to manufacture, largely because of the transition from the round forward boiler courses to the square firebox wrapper. 

The ICC, which controlled all the rules and regulations before the FRA's creation, originally mandated that steam locomotive boiler designs had to be built to a "Rule of 3": The weakest component of the construction had to be rated for 3 times the normal operating pressure. So in the case of the PRR K4s Pacific and L1s Mikado, which used the exact same boiler package as a standardization move by PRR, their 205psi boilers had to be able to handle 615psi. I'm not going to even pretend to understand the calculations involved, but it involved thickness of the firebox sheets, the number of staybolts, the staybolt spacing, and other factors. 

PRR was constructing almost 1000 identical boilers in 1914 (425 for the K4s and 574 for the L1s) and so, to save money on materials, they designed them to just barely clear the ICC's regulations. They went as thin as they could get away with on the firebox sheets and used staybolts threaded into the firebox sheets. That's not to say that this was an unsafe design, there weren't K4ss and L1ss blowing up left and right or having crownsheet failures all the time, its just that they didn't have as high of a threshold for total failure as the ICC wanted.

Sometime in the early- to mid-twenties, the ICC went from a factor of safety of 3:1 to a factor of safety of 3.5:1. The PRR firebox design was designed to just barely squeak by at 3:1, and so they had to do a quick redesign to make their primary passenger and freight locomotives legal again (I can't find if this also applied to the H8/9/10 Consolidations and I1sa Decapods as well, or the later M1a Mountains that used the I1sa boiler package). The solution was to tighten up the spacing on the staybolts and to thread the staybolts in through the firebox sheets and install a large washer with a nut on the inside and outside of the firebox to give a larger footprint. This basically made it just squeak by the 3.5:1 factor of safety and made them legal again.

So in 1985, PRR #1361 was taken off it's display plinth on Horseshoe Curve, moved to Altoona, and overhauled for excursion service. The quality of that restoration was a bit slapdash, it never actually operated properly during the year and a half that it did run, and in 1988 it suffered a bearing failure that cracked an axle. It was indefinitely retired and in 1996 it was moved to Steamtown in Scranton for another restoration. This was to be a complete overhaul to repair the issues with the original 1985 overhaul, damage that had resulted from it's year and a half of operation, and make sure it would have years of safe, trouble-free operation. Part of that included cutting out and replacing all firebox segments that were below 75% of the original thickness.

So, what happened? Well, one factor was that in 1995, Gettysburg Railroad melted the crownsheet on their ex-CPR Pacific, causing an investigation by the FRA and a revision of steam locomotive regulations, which were released around 1999-2000 and included moving the factor of safety to 4:1. Another was that the folks working on the #1361 were just operating under the thought process of "Well, the design was safe then, it should work now" rather than doing their math and consulting the FRA. They had spent a fortune on patching the firebox, and were going to start reinstalling staybolts and an FRA inspector came and took one look, did the math and said it wasn't even going to come close to meeting the "Rule of Four." In fact, it wasn't even going to meet the old 3:1 safety ratio.

See, after the revision in the '20s to make them legal again, PRR then ended up reverting a number of locomotive back to the original 1914 design during WWII, going back to the wider-spaced staybolts that were just threaded into the firebox. This was done during WWII, and may have been a way of working around material shortages or speeding up repairs to keep power in service, and the #1361 had received the backdated firebox design at some point in it's life. But the other problem was that the PRR's original design had an issue that no one had noticed: there was no provision for any sort of corrosion or wear. The new thickness was basically the same as the discard thickness. Accounts from those who had worked at Altoona was that basically PRR had fireboxes and wrappers made up for the K4ss and L1ss and treated them as a disposable maintenance part: when a K4s or L1s came in for an overhaul, they just automatically knocked the firebox and wrapper off and installed a new one. During WWII, when they were running them hard, they were replacing fireboxes every 15-18 months. And so the #1361's firebox, which they had spent serious time and money replacing any segments below 75%, actually still failed because basically, something that was 98% of the original thickness still failed, and they were going to have to redesign it all anyway to go to the "new" staybolt design and pattern.

Basically at the point, they had burned through $1.7 million, had a locomotive that still had a firebox that wouldn't meet FRA specifications, and they hadn't even touched the running gear. The RRM made some wacky half-assed plan that they were just going to reassemble it and then derate the boiler to a point low enough where it would meet the factor of safety (ignoring the fact that that might not be enough pressure to even run the lubricator, or stoker, or air compressors, or even move the locomotive). By that point, an oversight committee came knocking, because the state of PA had poured a lot of the money into the restoration, and everything came to a halt.

Now, with the new restoration being handled by FMW Solutions and bankrolled by guys like Bennett Levin and Wick Moorman, the #1361 is receiving an all-new firebox made of thicker material (from 3/8" to 7/16") and I believe they will also be going to back to the revised staybolt pattern.

I have to assume that #1361, once operational, will pay a visit to Strasburg at some point, and if it does, I really hope they do an In-Cab Experience with it because I would love the opportunity to operate a K4s.

#1361 running on the old PRR Bald Eagle Branch, which is now the Nittany & Bald Eagle Railroad. Someone I spoke to said that there is possibly an agreement to run the #1361 on the N&BE once it is restored. Also, check out the Chevette and Grand Wagoneer on the left. 

NS derailment that looks like quite a mess...

Pete Gossett (Forum Supporter) said:

NS derailment that looks like quite a mess...

I saw that video, that was a hard hit. 

Taken from the article: "The tractor-trailer was waiting for a green light," authorities noted on social media. "He was carrying a 134-foot concrete bridge beam. Then, the crossing arms went down as the train approached. The truck driver was unable to get out of the way in time." 

Okay, but why was he blocking the crossing while waiting for a green light? You're not supposed to enter a crossing or an intersection unless you can clear it.

Saw that too, what a mess......

Amazing that the engineers survived. A testament to the design of the North American Safety Cab.

Fun fact: the first locomotives with Safety Cabs in the United States were five MLW M420Rs purchased by the Providence & Worcester. They were an M420W but rode on trucks off of traded-in Alco RS-2/RS-3s instead of the Dofasco Zero-Weight Transfer trucks. While the EMD DD40AXs that UP owned had wide noses, they weren't actually a safety cab. They were the same as an F45/FP45 nose and were basically just sheetmetal without the reinforced structure to make them a safety cab.

These were also the sole Montreal Locomotive Works locomotives bought by a US-based railroad. The story goes that P&W couldn't get a good deal on new power out of either EMD or GE and so they went north of the border.