I'm interested in seeing if there is any published documentation, from either Wabco or NYAB, about the 26-FNL schedule. The only reference I have seen in print is the page or two in the NYAB section in the 1980 Locomotive Cyclopedia.

In comparison, the older 26-NL system seems to be well documented, by NYAB Circular 105 (1/1966) and NYAB IP-74, Supplement 1 (3/1978). But documentation on the 26-FNL seems to be scarce, although I have seen quite a few systems in use.

I find it sad that there appears to be no more response now on this subject than there was when you posted about it in 2008!

One potential ray of hope: Bobb Losse mentioned in 2018 that the L&N 314 FA rebuild had been converted from 24-RL to 26-FNL. If you are not (although I suspect you are) familiar with that work, he might have documentation or special material providing at least some of what you need.

I've worked with Bobb the last 20 years on the FA project, so I know all about the air on that unit, and the others. Did a lot of the air work myself, all of which copies some of the Winchester and Western's former NKP GP-9s. There has to be more out there on the -FLN version than what's in the '80 Cyc., though. And I'd forgotten that I asked the same question in '08. Time flies!

There is some evidence that there are two versions of the NYAB 074-1 supplement (that covers 26-NL, dated 1978) and that the 'later' version of the piping is not in the PDF supplied through their technical service. Is it possible that this might account for an apparent lack of IPs for FNL?

The version of IP 74-1 that I downloaded years ago has one drawing, on page 19, that shows a 6-NR distributing valve with those ports 2A and 2B and a double check valve added. In the description of 'how it works' port 2A and the check are mentioned with regard to an independent application, but I can't make any sense of their description of a release. Might be me, though-

Pages 55 through 58 have drawings of the piping connections; single unit, MU , MU with MU-2A and an F-1 for interfacing with 6 equipment. But those drawings are for 26-NL with no double check or ports 2A and 2B. The mystery continues.

I have the impression that the FNL conversion became rapidly obsolescent, perhaps with the advent of accelerated release for interchange in about this period of the mid-Sixties, and that may account for the reported 'two versions' of 074-1 (with only the earlier, non-FNL diagrams currently archived, and as I'm beginning to think likely some of the 'missing' FNL documentation. This may be one of those things like the front-mounted stoker information from the late 1930s that has disappeared without a trace... remember all the fun going on with plugged ports and blind gaskets around this time.

I don't remember the source of the comment about the 'later' version of the piping arrangement, but I suspect if you track down contemporary printed versions of this you will find ones that are different from the 'archived' copy. I doubt they will have their own 'revision number' or other identifying data -- you will have to look at the detail pages to confirm.

(I'm sort of amused as a HPS grad at the similarity of this search to the Italian Renaissance: we're proceeding on the assumption that there WAS at some point reasonable documentation of the FNL system, and that we CAN find it in ancient source documents. The next step of course being to re-create the appropriate documents from what we know about operable FNL systems ... something I suspect you're one of the leading authorities on at present.)

I'm not so sure that accelerated release had anything to do with either version. The 26-NL, 1/66 Circular 105 documentation, apparently came out, as you mentioned, about the same time as accelerated release. The big 'selling points' seem to be less maintenance and less chance of flat wheels in an MU consist.

If the 26-FNL version became obsolete because of accelerated release, why is it in the '80 Cyc., a decade and a half later? Not trying to start an argument here, but just wondering why there is so little information available on that system.

And as an aside, thanks for the complement, but I do not consider myself as an authority on this or any other air brake system. I'm just an industrial electrician, specializing in control systems, that had the rare opportunity to help bring some LIRR cab cars back to life as locomotives.

Once the wiring was done on the first two, I moved on to doing an air upgrade. I guess it's because I could read the diagrams and manuals, and figure out how things should work. Plus I had W and W's NICE Geep-9s to look at for guidance.

In the mid 90's I purchased a several boxes of paper in order to get what I wanted and then slowly sifted through the rest. I remember a NYAB publication for 26-FNL that was only 4, maybe 8 pages with the centerfold being devoted to the piping diagram. To me it seemed like more of a sales brochure than a pamphlet.

I've looked through what papers I still have and can't locate it, for that matter I can't remember if I loaned, sold or did something else with it.

What I do remember is it was around 8-1/2x11 anf the cover was two tone in yellow/reddish brown spectrum, which may help someone locate a copy.

I have heard it stated from a couple of old, now probably deceased air men, that the 26-NL schedule was a "quick fix" to equip older locomotives with 26 in the cab to standardize operations without a major rework of locomotives that were serving out their last years of ROI.

I agree with Paul D on the quick fix of to get rid of the older air schedules and their associated cleaning requirement dates and the labor time and parts inventory/availability associated with the older schedules. As an example the 6N distributing valve incorporated many of the same components as the J1 relay valve and was relatively easily serviced (even on the shop floor).

It should also be noted that the application of 26FNL to new locomotives was not unheard of. The Reading's 26 hundred series SW1001's were all delivered with 26FNL and I suspect the reason was economic as they were as bare bones as you can get. It wasn't until speed control was necessary on the NEC that forced Conrail to equip them with Harmon Ultra-Cab that we put in full 26F equipment.

All things being equal the 26FNL does not give the flexibility of a full 26L system especially as related to making changes to allow for conversion from iron to HF comp shoes and the installation of train control equipment.

I also recall issues with handling them DIC unless the service limiting safety valve was adjusted way down.

Also accelerated release has nothing to do with locomotive air. It is a function of the cars control valve.

EBL

The Reading SW1001 reference brings to mind a story, perhaps an urban legend, that I heard years ago. I was told that when the PRR dieselized, they shipped a lot of salvaged steam air brake equipment to the diesel builders to use on new switchers. Included were things like 6-ET brake valves, 'pigs', and 6-K distributing valves.

Any truth to this? It seems like a reasonable cost savings measure; a brake stand just needs air, whether it comes from a steam compressor, or one driven by a diesel or electric motor.

Attached is the as delivered piping schematic for the Reading SW1001's

EBL

EBL-

Thanks for sharing that piping schematic; I'm not sure I had ever seen 26-NL or 26-FNL with a deadman before. That drawing is actually 26-NL, though. The -FNL version has the independent connected to the added ports 2A and 2B on a blanking cover added to the 6 distributing valve. I'm still trying to understand why they offered the later -FNL version, which is piped slightly differently and adds that cover and a double check valve to the mix.