From those who have experience, which is better to use, a Nathan Simplex injector or a Nathan Monitor injector? For discussion sake assume they are the same size delivery nozzles.

I am looking for information in the way of;
- maintenance
- ease of use
- noise level when functioning
- priming time

and any other factors anyone can think of!

The one in better condition is the one that is better to use. Both work well when in good shape.

Understanding the question he actually asked:

Assuming the injectors are in equal condition and state of repair, which design has better characteristics as requested?

I, too, would like to learn these things about injector designs, so please be detailed in describing what the features and problems with those designs have proven to be.

If that was the question, in my experience unless there's some sort of logistical issues involved, neither is better or worse than the other provided they are in good condition, and the associated piping and check valves are also. Sellars lifting injectors are also very good, on par with these, and Ohio clones also. Hancock Inspirators, though seem tricky and fussy in comparison. Your mileage may vary.

I would like to suggest that although they may be in similar condition they won't be in new condition and it has been my experience that the monitors, when worn, tend to lose more water the simplex. That said I can’t tell you that the monitor was as equally worn as the simplex.
I would first use the one that works best and then second the one that looks the coolest.

Greetings:
In my experience with both, I would choose the Simplex because it is primed by pulling back on the steam valve handle slightly where as the Monitor has a separate priming valve (probably why the Simplex is named thusly).
FYI, Valley Railroad has patterns for the nozzles used in the Simplex type "R" No.9.
J.David

In my opinion it depends on the service you are using it for. If your on a short, stop and go road engine, the Simplex would be my choice. Although I haven't used the Monitor, it looks like you can feather the feed back to suit the usage, better for a long haul engine, but the Simplex is either on or off, like a Penberthy injector. The only issue I have had with them in the past 15 years isn't with the injector but the starting valve. They are made of cast brass and over the years of use the bodies and seats have cracked. I tried fixing them but ended up reto- fitting a Sellers replacement from Strasburg RR. Should have done it sooner as they work flawlessly and just regular PM in the Fall. We also have a NOS steam nozzle and combining tube for the #10 Nathan Simplex (mud sucker :-)

Brian Manning CE/CMO
Heritage Park
Calgary

Nathan starting valve cracked seat in 3 different places, although hard to find, dye pen will find it easily.

Ah..... are we discussing lifting or nonlifting? I think JDC, Chris and I were talking lifting while Brian is talking nonlifting.

The easiest injector to use in my opinion is the Sellers Type N lifting injector. And by far the worst was a Gresham and Craven injector.

Just from personal experience not scientific testing.

KT

The worst starting gun I have had the pleasure of running was a Garfield. Ran good once started but a bear to start.

Sounds like a Metropolitan that I had to deal with many moons ago. I was glad that the other injector on the old girl was a Sellers.

I for one would like to see a little more experienced answer to the sort of specific questions he raised in the original post:



We have had valuable input but much of it seems to be assuming prior familiarity with the equipment and its use. An additional question is how some of the performance criteria change over time, or with normal 'wear and tear' due to practical operation ... or "typical" kinds of railroad maintenance sometimes aka benign neglect in the absence of emergent problems or imposed discipline...

OK. The innards and shells of both are very similar, it's the valves that are different. So, the noise factor is the same. Some people like the separate priming valve / steam valve better than the one lever actuated ram, some find the ram works fine for them. The cam operated poppet water valve is not as easy to fine tune as the screw water valve, but that isn't necessarily important depending on your operating practice - leave on and regulate or use in short doses. If you have issues with water quality or foaming or other things that lead to valve seat erosion, there's one more seat to maintain with the screw valves than with the ram. In any case, you want to address valve seat problems when they are small and easy to lap out. Changing tubes or nozzles is the same on either, the problem is finding new tubes or nozzles. So, for me it's a tossup - use what works best for you.

Maintenance - if you haven't got them crammed into a small space, you can do the most common work - valve steam packing and seat lapping - on the locomotive in both types. They fit interchangeably on the same pipe bracket, so removing them for bench work is equally easy (or difficult).

It's kind of like choosing between two credit cards when you pay both off every month. Unless you have a small customer rewards difference of some sort, it doesn't matter which you use.