Getting it Right:
Re-detailing The Bachmann On30 Climax
Oil Tank Details 101 & Oil Filling Hatch Body

Bachmann Climax Conversion to Date (August 15, 2011).

Oil Tank Details 101:

Before we start adding details to the oil tank, it’s important to know what parts we need to add and what they do. Otherwise, we’ll end up with model like the typical brass import: a generic box for an oil tank with a water filling hatch for an oil hatch and maybe a dipstick. The oil firing controls are almost never added to the backhead, the burner supply pipe and superheater are usually missing from the locomotive, the oil tank heater piping is usually missing, and the oil tank shut-off valves are almost never on the tank or where they should be (and usually not in the correct closed/open positions). Bachmann is unusual in that they actually put a supply valve handle on their oil tanks and in the correct “open” position (but not in the correct location). So, what parts do we need to add to our oil tank? (see diagram below)

General Oil Tank Arrangement Diagram (not really any specific locomotive), from International Library of Technology, 267C, Locomotive Operation, (Scranton, Pennsylvania: International Textbook Co., 1925) ILT 68C, 267C §20, Figure 2.

Ouahu Railway No. 85’s tender, a fairly typical oil tank arrangement for narrow gauge engines. Local bra…, er, children have removed the dip stick and handles for the oil feed and tank drain valves. Photo by Jerry Kitts, Travel Town, Los Angeles, CA circa early 1970s.

Oil Filling Hatch:

The most obvious/visible part of an oil tank. While constructed similarly to a water tank hatch, there some very important differences. The basic tube shape is the same, but, there should be an additional ring at the top to support the lid (or “Manhole Cover”) and to mount the wire basket suspended inside the hatch that acts as a strainer. This lid is also a bit more complicated. Water hatch lids can be simple hinged affairs or simple plug lids that held in place by gravity. Oil hatch lids need to be dogged down because the oil tank can become pressurized either by using steam to heat the oil in tank or by the gasses coming off of the oil on hot days. This leads to two general kinds of lids: a plug lid held on by 3 or more (usually six) hinged dogs evenly spaced along its perimeter or hinged/pivot lid held down by a couple of hinged dogs (the diagram above shows the pivot type). Oddly, lid handles are fairly rare. Which must have been fun for the fireman considering how gooey these lids got in use. When they were’t using the tank heater, fireman generally got lazy and used as few dogs as possible to keep the lid in place.

Dip Stick (Oil Measuring Rod):

Same concept as the oil dip stick on car’s engine (or, rather, your car’s oil dip stick is just like the dip stick on an oil burning locomotive, as steam engines came first). Instead of a thin metal strip with basic “Go/No-Go” markings, the dip stick on a locomotive’s oil tank is a square steal rod about 5/16″ wide with graduated markings along its entire length giving the depth of the oil in the tank. I have yet to find an oil tank with the depth/capacity chart plates on the front. The stand pipe that the dip stick passes through is exactly that, a 1″ pipe mounted in the top of the tank. It should be tall enough to support the dip stick and keep it from swaying from side-to-side in the tank. Some larger tanks had two dip sticks. Obviously, the dip stick needs to be positioned over the deepest part of the tank to be of any use.

Oil Feed Valve:

Technically, the handle for the valve (which is inside the tank). These handles have several different forms, but all operate in essentially the same way. A spring loaded plunger inside the tank is retracted by a handle that toggles between the “open” and “closed” states. The valve handle can be either on the top or front of the oil tank, but the valve itself will be on the bottom of the tank on the fireman’s side. This quick acting valve can act as an emergency fuel shut-off. Should be in the “open” position on an operating locomotive.

Drain Valve:

Identical to the oil feed valve, only leads to a drain pipe on the engineer’s side (not really shown in the diagram above correctly). Should be in the “closed” position on an operating locomotive.

Tank Heater Steam Pipe:

“Bunker C,” the kind of oil used as fuel oil, is a very thick, viscous oil. As such, you have to heat it up to get it to flow out of the tank in very cold weather. This can be done two different ways: with a coil of stream heated pipes inside the tank or, more commonly, by blowing hot steam directly into the oil near the oil feed valve (as shown in the diagram above). A steam pipe coming off of the turret travels under the floor of the cab, up the outside front of the oil tank, through a check valve, then into the top of the tank (small engines usually only had one pipe going into the tank). The steam was then vented out of the tank via another pipe if coils were used, or the condensed water would flow out of the tank through the oil feed valve and get ejected through the burner in the firebox.

Maintenance Hatch (not shown):

Sometimes, if the oil tank is big enough to accommodate it, a circular metal hatch is bolted over a circular hole to allow access to the valves and pipes inside the tank for maintenance.

Sand Box:

If there is enough room to accommodate it, a sand box is placed in front of the oil tank. The sand is used to “sand the flues” or a scoop or handful of sand is allowed to be sucked from the firebox door (via the draft) through the flues to remove soot and build-up. On a small locomotive like this where space is at a premium, a galvanized bucket of sand is used.

Adding the Oil Filling Hatch Body:

Time to design and create an oil filling hatch. Photos of prototype, oil burning Climaxes are, unfortunately, extremely rare. This is made worse by book publishers penchant for only including front, 3/4 photos of locomotives. Luckily for us, Pacific Lumber No. 38 is an oil burner. From what I can see in photos of oil burning Climaxes, they tend to use the simple plug lid (aka don’t use tie down dogs, though there are some that do) for the oil hatch, as does Pacific Lumber No. 38. This would suggest that it used a coil-type tank heater. I haven’t yet been able to find an exhaust for a coil heater, but that doesn’t mean much as the plumbing on Pacific Lumber No. 38 has been badly mangled over the years. For some strange reason, whenever a valve or pipe failed, the repair seemed to be to add yet another valve in line, rather than repairing the failure. A good example of this is that the tank drain and oil feed valves seem to have failed; so, the “repair” was to screw another valve directly into the base of the failed valve! The coil heater may have failed and, rather than repair it, they may have just left the steam heat input pipe in place and removed the exhaust.

Pacific Lumber No 38’s Oil Filling Hatch, a simple plug type.

Modeling this style of oil filling hatch is as easy to do as the water filling hatch. Some easy lathe work, but with a flange on both ends of the tube instead of just the bottom. This will be the type I put on the steel cab, squared-off oil tank Climax with straight load fence sides I’m doing later.

The type of lid I chose to model on this engine is the kind held down by dogs. Luckily, several examples of this type of lid still exist in many museums. The Roots of Motive museum in Willits, CA has several (unfortunately, Mason County Logging Co. 2–6–2T No. 7 and North Bend Mill & Lumber Co. shay No. 2, the “Robert Dollar” shay, both have modern replacement oil hatches). California Western Railroad 2–6–2T No. 14 and Bluestone Mining & Smelting Co. heisler No. 4 both have their original oil hatches. Nevada County Narrow Gauge No. 5, currently in the NCNGRR Museum in Nevada City, has a very typical oil hatch on its oil tank. One that I was able to photograph and measure while the oil tank was still being stored in a field at the museum site.

The remains of California Western Railroad 2–6–2T No. 14’s oil hatch. It’s hinged and 3 dogs. Photo by Scott Kitts, at Roots of Motive Power, Willits, CA, 4/14/2011.

Bluestone Mining & Smelting Co. heisler No. 4’s oil filling hatch. It’s a cast, handless, dogged lid with 4 dogs. Photo by Scott Kitts, at Roots of Motive Power, Willits, CA, 2/09/2005.

Nevada County Narrow Gauge 2–6–0 No. 5’s oil filling hatch. It’s fabricated (meaning it isn’t made of cast parts), with a dogged lid with 6 dogs (both original and fabricated replacements). The wire basket, lid, and several whole dogs are now missing. Photo by Scott Kitts, at NCNGRR Museum grounds, Nevada City, CA, 2/01/1998.

Nevada County Narrow Gauge 2–6–0 No. 5’s oil filling hatch simplified overall drawing.

I decided to go with a completely fabricated oil hatch with 6 tie down dogs (equally spaced, 60° apart), using NCNGRR No. 5’s oil hatch as a guide. No. 5’s oil hatch is 18″ in diameter and 12″ tall. It is attached to the oil tank with 3/8″ bolts through a 2″ flange. The rim on top is actually two pieces riveted to the main tube, but the net effect is that it is 1 ¼&Prime tall and 3/8″ thick. The lid appears to be a flat piece of sheet metal without a handle approximately 22″ in diameter. The offset, hinged bolts of the tie down dogs are ½″ threaded rod. This gives some nice, prototypical dimensions, but I wanted to vary things a bit. Since the bottom mounting flange can be either on the outside or inside of the main tube, I though being on the outside would be more interesting. I also used rivets, instead of bolts to same myself the trouble of finding really good 3/8″ NBWs. I also decided to go with a completely fabricated plug lid (the rivets hold the inner, telescoping ring) with a handle. This should make for a fairly interesting looking, intricate part on the finished model.

Just as in the case of the water hatch, I’m sure PSC has a part that would suffice, but I’ve found some the brass castings out there a little disappointing (usually in the area of the tie down dogs). Again, just like the water hatch, the main body of the oil hatch is a fairly easy lathe project, with a little help of an indexing head and a mill for all the holes. But why let a CNC mill go to waste? The trick to using a CNC mill to make a part like this (since undercuts would be difficult), it carve the part into sections you can mill. In this case, adding the upper ring to the lid instead of the vertical tube made the parts easily machinable and had the added bonus of automatically centering the lid when assembled. I also doubled the thickness of lid (which is only 0.010″ thick) inside this ring to help keep the wire for the handle straight.

Raw Plexiglas oil hatch parts. The two different lids are upside down and have the upper ring of the oil hatch tube machined onto their bottom sides.

Raw Plexiglas oil hatch parts test fit together.

6 dog oil hatch installed.

Now all it needs are the tie down dogs.

To Be Continued…

©2011, Scott Kitts. All rights reserved.

Rev. 3/28/2014.



Go to Previous PageReturn to Modeling Guide Table of Contents