Why Weren't Duplex Steam Engines Successful?

Soundtrack: All Available from the YouTube Audio Library
-Distant Lands
-A Night Alone
-Swing House
-Subtle Betrayal
-Anchors Aweigh
-Devine Life Society
-Good Gig In the Clouds
-Greaser
-Sunday
-Monument

[CL-handle]

What's the background music that plays from 2:56 to 5:36?

[RTracing]

if you spoke to PRR engineers who piloted the T1's the majority of them would say that the wheel slip problem was a myth. The final analysis of this piece of railroad lore was that the engineers were not used to so much instantly available power, and that was the true cause of the perceived wheel slip issue. But as noted, most of the engineers were of the opinion that once used to the available power, and how to manage it, the wheel slip issue was non existent. But rumors, myths and folklore are hard to dispel, especially among non railroad individuals and rail fans.

[kccvh]

What's surprising is how little the steam locomotive changed between 1870 and 1940. Mostly they grew in size and power, the most notable changes in the design were the addition of superheaters and feedwater heaters in the World War I era. No thought was given to a fundamental change such as use of a rotary positive-displacement expander, such as the scroll device patented in 1912. This would have eliminated the dynamic augment issue and greatly increased efficiency, but there was no incentive for change. The railroads had long been a complacent industry, having no competition except other railroads using the same equipment and methods, so they were caught flat-footed when the 18-wheelers and Interstate highways began to appear.

[Thunderbolt__Siren]

As a PRR guy the video is mostly positive. They were definitely ahead of their time in many ways especially in terms of electrification and steam technology (hence why the GG1s built in the 30s would refuse to retire until 1983 when they physically got too old) the problem is while they embraced new technologies, they had a habit of keeping the old ones a little too much. That doesn't deny the fact they we're truly "The Standard Railroad of the World" and one of the best fallen flags out there. As for 5550 the organization is actually not far from home (being started in Pottstown PA) and with the lessons learned from her predecessors 5550 will definitely be the ultimate steam locomotive. Certainly looking forward to the completion, besides if the British can build new steam from the rails up like Tornado, we can do it too!

[vermas]

The S-1 still looks absolutely amazing. I wish it had been designed a bit better with its weight. And been preserved...

[iLikeTheUDK]

Regardless of how practical or impractical they were, they definitely looked fantastic

[azuma]

Discovered this channel only a while ago, definitely one of the best channels for American loco history. 😊

[raxcentalruthenta]

I love how the T1s look. They have a very modern appearance.

[sequoyah]

A friend's grandfather was a mechanical eingineer for the Santa Fe. As young engineers at school we read his reports on front end design (stack, draft and cylinder exhaust), coal testing, valve gear and other subjects with fascination. In its heyday rail was a huge industry featuring in every day life across the country and not so much in the background as it is today.

Coal quality testing was done with dynomometer cars and a test engineer over a standard section of track with a dedicated test engine so that consistency of the testing would be assured.

One of the best parts of the reports was the professionalism and precision exhibited. No sloppy opinioneering was seen.

[pacificostudios]

I like your theory about the PRR's engineers pulling the T1 throttles too fast. The great mystery is the entire Q Class. The PRR was always a 50 MPH freight railroad, with much of its cargoes being open top coal hoppers. That fact is why the PRR rejected the N&W Class A 2-6-6-4 locomotives, which they tested when they were considering the C&O T-1 2-10-4. That's probably also why PRR did not try the Challenger types (4-6-6-4). So why build such complicated locomotives with 69 inch drivers as the Q's? Thanks for promoting the T1 5550 project!

[russellgxy]

For every great aspect of the duplex, there’s always a drawback and that kinda why I like them. Especially the T1’s. I always figured the T1’s were a tad too powerful for what Pennsy crews were used to, and this basically confirmed that.

Something else to note about the T1’s trials on the C&O was _their_ experience with some of the T1’s qualities. Staff were already rather familiar with multi-cylinder engines, even if they had a hinge in the frame, and they would’ve had some experience with poppet valves thanks to the recently rebuilt L-1 Hudson’s and possibly the L-2-a’s. The PRR wasn’t familiar with either of these so of course they would slip with a yanked front-end throttle. Splitting the drivers was probably a detriment in that regard, since each driving set had less wheels to recover from a slip than a Pacific or Northern type. In that regard, it was probably for the best that the Pennsy chose a 2-10-4 for its War Baby rather than a 2-6-6-4…

[Pensyfan]

Great video on some of the Pennsy’s greatest engines. It just so happens that my channel gained 5k subscribers today, and I changed my PFP to reflect more of the Pennsy’s heritage, so seeing this video today is a bit of a good omen.

[mechamax]

here's to the newest T1 to be built, and hope it can break the steam speed record in the process!

[tokyoarrow]

I’m from Darlington, England. The world’s first passenger locomotive was built about 100 meters from where I grew up! The new steam locomotives, Tornado and Prince of Wales were also built at the same location and now run on the main line between London and Edinburgh (and stopping at Darlington of course).

[maegenyoungs]

I’m not a train nut like most of you on here, but damn these things are beautiful. Something about more wheels, just looks amazing

[herbderbler]

Reminds me of some of the absolutely gorgeous machines from the flying boat era, such as the Saunders-Roe Princess and the Boeing 314 Clipper. The jet age came along and jet engines became the standard for truly large aircraft, plus the boom in passenger travel saw ground-based airfields transform into massive airports as we know them today. Flying boats just weren't needed anymore and that unique era of aviation passed into history.

[brushbros]

The power required to propel the locomotive itself was considerable. Such an interesting video.

[matthewpowell]

Excellent video! I myself am a heavy duplex fan. Even though it was infamous, PRR 6100 is my second favorite steam locomotive. And I believe that if diesels didn’t interfere, the duplex could’ve reached its full potential and maybe have kept steam in revenue earning service for a longer time.

[fmnut]

Excellent documentary, well researched, well illustrated and edited. I also appreciated the impartial presentation of facts without the misstatements, positive hyperbole or negativity in other "documentary" style videos. Thanks for your efforts, I understand the amount of work that goes into creating content like this.

[northpennvalleysteamrailroad]

With today’s technology, T-1 5550 will be better than any other duplex steamer ever built!

Edit: how did this get 114 likes?