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Great photos, interesting news! I always like to see what is happening at SRR.

What is entailed in converting crankpins to oil lubrication?

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That is a very interesting concept in the details of that oil cup. If I understand it, you have what amounts to a small free piston that reciprocates up and down in reaction to the up/down movement of the crank pin as it rotates. And the piston stroke can be adjusted by the top screw. But I cannot quite understand the drawing in the detail of the piston. It appears that it runs in a cylinder bored through that screw-in pedestal, and the pedestal is cross-drilled to let the oil into the valve port ahead of the piston. It almost appears as though there are two pistons; one raised up into an open position above the valve port, and another nested down into the port. I don’t understand those two short radiused dotted lines crosswise to the diameters of the piston and valve seat bore.

I can see two possible functions of that little free piston. One would be that it opens and closes against a seat like a valve. The other would be that it actually acts like a piston and functions as a pump to inject oil in measured strokes. If it functions like a valve, I don’t quite understand how the adjustment screw affects the delivery rate.

When did standard practice change to grease instead of oil, and what was the reason? Did this 1906 design of oil cup reach a near universal application as a standard state of the art design that was then eclipsed by the practice of grease lubrication? If the trend indicates that grease was an improvement over oil, why are you reverting back to oil?

RTK

Don't recall hearing anything in a while. Has any further evaluation been done on the Reading camelback?

The drawing can be confusing to read, especially these old hand drawn drawings. Draftsmen had some variation in standards. The way I read the drawing, the free plunger is two diameters joined by a seat in the middle. The smaller diameter has clearance to allow oil flow. The dotted, curved lines you see above the seat represent the curvature of the tunnel running through the valve block. The cross hole is round, and the intersection of two round holes creates the dotted lines you see.

Yes I think you are right. The plunger has two diameters. It is not sectioned, and the dotted lines are the hidden features of the intersection of the two round bores. I can also see the clearance in the fit of the smaller diameter of the plunger. Thanks for your help. That makes perfect sense.

RTK

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I have an oil cup that I found with a metal detector. Evidence suggests that it came from an 1882 Manchester engine. It has a threaded cap with an adjustable needle valve and locknut. However, there is no reciprocating free piston. Instead, the threaded valve stem has a long tapered needle that opens and closes by adjustment. The needle seats into an orifice in the center of a small basin atop a raised pedestal. The basin and pedestal appear to be part of the reservoir body casting.

The upper part of the housing reservoir and top cap develops into a dome shape, so as the cup drops on the down stroke, the oil is forced up where it converges toward the center as it encounters the dome, and wets the valve screw. Then it runs down the screw and collects in the basin. I suppose the upstroke has a tendency to then force the oil in the basin down into the valve port.

So this is like a two-stage pump with a reciprocating cylinder and no piston.

RTK

Up at the WW&F Ry in Maine we've applied oil cups to our 1904 Vulcan Forney, and after a lot of experimentation settled on this design:

We use journal oil year round, but this is a much lighter load than the Strasburg's 475 has. We have noted a fair amount of wear on the main pins, but have not had problems with heating, so the wear is a bit of a puzzle.
However, we went two seasons with a variety of designs that had a variety of problems, mostly throwing the caps off onto the ROW! This is the first season that we've had consistent and controlled lubrication.
As you can see from the cross section, the oil has to splash up to the top of the adjuster screw, and then it can flow down through the center hole and the needle valve and to the rod bearing. We found that it needed a way to relieve the vacuum that would form, so there is an air vent in the top. The drawing doesn't show that there is a spring under the adjuster to keep it from rotating, or that these have a 1/3 turn twist off type of cap for easy filling.
This is designed to provide oil at low speeds, so that under the heavy thrust and low rotational speed during starting or low speed lugging there would be sufficient lubrication. We use about 3 tablespoons per 10 miles, which is probably too much, but safe enough.
Our experience was that anything that was allowed to move would quickly pound itself silly, but I suspect in the design Strasburg used which has the moving valve piece, the oil itself cushions the impact.
These cups are screwed into the rod above the bearing, and are made from brass.
A question I have after reading Mr. Anderson's post is: should we experiment with a heavier viscosity oil? What was the experience that you had with journal oil: overheating or excessive wear?

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Ah yes, Poor Pappa Boul, and Burt Lancaster re-babbiting those rod bearings afterwards. Gotta love the way he hefted those big mains up on the engine and the part where they ran the train in a big circle, with fake station signs. But I digress..

Anyway, thank you for the information. Interesting and encouraging that Thomas doesn't show any pin wear.
I would think that the eccentrics would have a higher surface to surface speed and so be a better application for the thinner oil. The eccentrics on #10 get the same oil and seem to be wearing well.
Our experience is that the car oil tends to run through a small opening pretty fast, as the centrifugal force is quite high even at low speed and the car oil's viscosity is somewhere lower than the 10W30 I put in my auto. If you were running out of oil pretty quickly, could that partially explain the hot bearings? Our 12 ton Forney's got split brass bearings, as opposed to the press-ins I see on the 475, so the entire situation is likely quite different, but I don't have any experience other than on this particular small engine we have.
However, I will chat with our MM, Jason Lamontagne, about other oils. I know he's interested in a biodegradable oil.

Hi Everyone:

I thought I might jump in on this thread as the Green Velvet champion. I think Kelly is correct - pin greases replaced oil rod lubricators when engines were pooled and became traffic machines rather than "pets" of specific engineers assigned to a particular engine. Greases are oil impregnated soaps that are retained in rod cavities. The oil in the soap thickeners is released from the grease when temperatures in the rods rise to a level high enough to drive the oil from the thickener. At this point the oil lubricates the bearings and will continue to "feed" and build films as long as the grease stays in the rod cavities and there is oil remaining in the soap base. Modern grease thickeners like Lithium soaps have a dry lubrication characteristic that assists with lubrication, but the oil does the majority of the work. This arrangement is simple and assures lubrication of the rods as long as somebody keeps the rod cavities full of grease and don't allow them to run out on the road.

The most important distinction to make about lubricating oils is the understanding of "100% loss lubrication" as opposed to "re-circulating lubrication". Locomotive rod lubrication is 100% loss lubrication. The oils mentioned, such as journal oil and the gear oils used at Strasburg are designed for re-circulating service. This means they are intended to be used in applications where the bearings are more or less flooded with the lubricant. When this action occurs they build sufficient films to maintain good boundary lubrication or, better yet, dynamic lubrication films. However, in a rod application (and most other applications on steam locomtive running gears the lubrication systems apply a small amount of oil that is lost to the surrounding environment when it is expelled or drips out of the bearings.

As a result car journal oils are poor running gear lubricants because their marginal application only provides thin, medicocre films that disappear almost instantly if the lubricant feed is interrupted for any reason. They have poor film retention and require almost contant monitoring and fiddling to get satisfactory lubrication. In a friction type car journal the pads are constantly wicking these SAE10W-20 oils up to and on to the underside of the journal and then up into the bearing surface. Once the car reaches about 15 mph a oil wedge forms and the "friction" bearing achieves dynamic lubrication where there is no metal to metal contact between the brass and the journal. At this point there is almost no difference in rolling resistance between roller bearing cars and friction journal cars.

This is not the case with locomtive running gear which always stays in the boundary lubrication mode where the bearing and journal are always in contact with one another. Lubricants designed for these applications must build tough, tenacious films that assist the metal surfaces in sliding over one another without galling and excessive heating.

Common gear oils such as those mentioned by Kelly are not 100% loss lubricants, but are designed for re-circulating service in gear boxes. Furthermore, they must perform as coolants and many gearboxes utilize water cooled heat exchangers to pull frictional heat out of gearboxes via the re-circulating oil to keep them from burning up. Many times these oils produce mediocre films in 100% loss lubrication systems because they are not intended to have good lubricant retention in bearings - they are required to flow freely because large re-circulating quantites are required in gearboxes to carry heat away from the meshing surfaces of the gears. While SAE90 and SAE140 single weight gear oils that are used on locomotive running gears can provide adequate lubricating films, they generally require high consumption feed rates because they have poor retention characteristics in most types of open bearings. In other words a lot of gear oil is left at the station because it ran out of the bearings before the train left on its trip.

Another concern with gear oils is their classification as "EP" oils. EP stands for "extreme pressure additive" which is required for many gear meshing applications where extremely high surface stresses "shear" normal oil, thus breaking down lubricating films and causing premature gear failures. Many EP additives are known to attack and cause corrosion on copper based alloys (bronze locomotive bearings - "brasses"). Does your gear oil contain bronze corroding EP additive? Beats me! The major oil companies are not in the habit of discussing their ingredients with customers. Also, they change blending components on a random basis without notice. Just because your oil doesn't corrode brasses now does not mean the next drum won't at some time in the future.

As environmental concerns become more prevalent the ultimate fate, or biodegradability of 100% loss lubricants is becoming a major concern. The first order of environmental stewardship is to provide the locomotive with a high performance lubricant that requires very low feed rates while providing superior lubricating films. Loss of these small quantities into the environment then requires proven "readily biodegradable" characteristics that can be proven and certified by tests that are accepted by state and federal environmental jurisdictions. None of the lubricants mentioned in these threads is certified as readily biodegradable and can create unimaginable trouble if contamination of ground and ground water is cited by the local environmental jurisdictions.

The Green Velvet PB&J (Pin, Bearing & Journal) Oils, the Chelesic Biodegradable PB&J and the (now under development) Chelesic Biodegradable Non-soap Pin Grease have been developed specifically for 100% loss lubrication on open type steam locomotive bearings. Field feedback suggests they are performing well in these applications. If anyone would like to discuss these oils and greases further please contact us.

Bill Petitjean
billp@steamenginelube.com

Bill,

Thanks for additional info on lubrication.

I'd bet the oil Kelly is using contains EP additives; all the 85W-90 and 85W-140 gear oil I'm aware of is for hypoid gear service (auto ring and pinion gears) which require the EP additives.

The one major downside I can think of about using gear oil for the rods is the smell! Gear oil is some rank smelling stuff. Hopefully it won't overpower the aromas of valve oil, coal smoke, and steam.

Thank you for your detailed explanation of lubrication realities. I find it very useful to understand these basics so we can make the best use of our old technology/new technology situations.
I wonder if Mr. Anderson's experience with Thomas's eccentrics is because of the low speed-high load problem where during starting the oil film is thin because it's been sitting, and the surface to surface speed is low, and the eccentric bearing pressures are high, so that a really tough oil film is needed to keep the metal to metal contact to a minimum? As Mr. Petitjean notes, the grease would provide better lubrication under those conditions than the journal oil. It's my understanding that a brass or babbit on steel rotating bearing will tolerate that condition better than a cast iron on cast iron bearing.

I'm assuming that Thomas has unbalanced slide valves which require a lot of force to move under a heavy throttle? This is the situation on our 1904 Vulcan, and this discussion has given me something to think about.