Independent PTC. UP has published some pictures and discussed some aspects of the system.
2816 has independent PTC, something their steam crew is very proud of. So proud that they don’t want to discuss any technical details at all, and keep it ‘proprietary’ (one member of the crew said that since they put 2 and a half years of work into it, they’re not just giving the ‘secrets’ away.)
U understand 2926 is to have independent PTC (not dependent on a link to equipment in a diesel or support car) and would appreciate seeing whatever approach they have implemented.
What this calls for, in my not-so-humble opinion, is a Firecrown-supported technical article in the new Trains, going into detail about what is required to implement ‘correct’ PTC on a steam locomotive and how the different railroads that are doing it met the challenges.
And for old time’s sake, here is pre-PTC Challenger 3985 including some rare mileage at track speed on that mighty good road to St. Paul, MN in 2008.
That would interest maybe 2% of the readership.
Here is a 15-inch gauge 4-12-2 “almost” Union Pacific type that is under construction at Merrick Locomotive Works in WI.
First one is a running gear test.
Second one is near completion.
You will note left-side-mounted air pumps, two cylinders and rectangular tender with six-wheeled-trucks as differences to the 9000s.
https://m.youtube.com/watch?v=MUiF0WHnl_U&pp=ygUUMTUgaW5jaCBnYXVnZSA0LTEyLTI%3D
https://m.youtube.com/watch?v=PcI5UcW1T0k&pp=ygUTd2hpc2t5IHJpdmVyIDQtMTItMg%3D%3D
Here is Big Boy 4014 in the 1950s in regular operation:
Some incredible color film of Big Boys and other steam:
https://m.youtube.com/watch?v=VDdakciBQVE&pp=ygUcdW5pb24gcGFjaWZpYyBiaWcgYm95IDE5NDBzIA%3D%3D
Here is an all-color snippet of UP steam on the Kansas Division in the 1950s including a 9000 Union Pacific, several 3800 Challengers, FEF Northerns, a 7000 Mountain and a 3200 Pacific really making time.
Running a 9000 out of Council Bluffs:
https://m.youtube.com/watch?v=8YhtAYraQc0&pp=ygUadW5pb24gcGFjaWZpYyBzdGVhbSAxOTUwcyA%3D
Thanks, kgbw49. I don’t think I had ever heard a three-cylinder locomotive running before. Weird.
Anyone else note 844 on the board?
E7B assigned to the stock train?
Boxpok outside main?
4014 Highball!
(~six minutes of pacing in Wyoming - 2023)
Go west, young man.
Big Boy heading west as God and Otto Jabelmann intended:
https://www.railpictures.net/photo/860760/
Please remind us of the various functions the “support diesel” provides, beyond PTC, and if intermittent or continous.
Is it possible to run without ANY “support diesel”?
Anything is ‘possible’, however possible and UP protocol are likely two very different things.
Ah yes, what former poster Juniatha used to call the “Panic Diesel.”
Steve Lee explained it years ago. Since the UP is an active railroad and not a “tourist line” for lack of a better term the lines have to be kept fluid and active as the shippers always come first. The diesel’s there as a back up to keep the train moving just in case the steam locomotive fails.
In fact though the reverse was true on one occasion, the diesel failed, as in failed to shut down, and pushed 844 down the tracks causing flat spots on 844’s drivers!
If you notice from the June 30, 2024 pictures there is no support diesel.
UP’s installation of PTC on 4014 apparently has worked to satisfaction.
Tis’ Nice to see Steam running as intended,
I believe that another much appreciated, if not necessary benefit, is Dynamic Braking
Doug
The whole point of the independent-PTC efforts (as on 4014 and 2816) is to allow them to run without ANY “support diesel”.
As Doug just mentioned, while the diesel does give rapid and immediate ‘limp-home’ capability for a range of road failures – although, perhaps important to note, not all – the single most useful thing it can provide is not enhanced tractive effort but dynamic braking.
As was discovered on GG1s operated with Amfleet equipment, if the locomotive is very heavy, the amount of required train braking force can become great at times, particularly from high speed, but the independent brake on a steam locomotive is a relatively crappy and potentially very expensive way to provide that. I remember for example that when 3751 was restored, it had to be tested with a substantial rack of skeleton flats to provide sufficient braking ‘wheels and shoes’ to be safe. Now, if that can be done proportionally, and fully graduated, without any need for friction braking… which is something dynamic braking provides, on modern locomitives right down to almost zero mph road speed, you have an advantage.
Another is drifting control. Most steam locomotives have to have careful handling when drifting at speed (this was one purpose of the Wagner bypass valves, as on ATSF 2926, and technically for the Trofimov valves on some Chinese steam) and there are advantages in being able to work for example ~15-20psi positive steam pressure in the engine to prevent vacuum effects or the usual problems with allowing atmosphere into the cylinder space via snifter valves.
If there is any sort of developing issue with water, or with coal or oil quality, having diesel power to be able to ‘stretch’
It is nice to see 5 clean boxcars, 7 clean grain hopper cars, and the Steam Program caboose in the consist, all to help with the braking as Overmod points out, but also making it a great-looking train!
Good stuff from UP!