On the assumption that the boiler was the most difficult and expensive thing to repair, for the last several years we have been concentrating on removing tubes, cleaning off scale, and ultra-sounding the boiler for our 2-8-2T logging mike. Now, getting more down and dirty, we discovered several welds in the frame. We are in the process of having them checked by a NDT outfit, to determine how good, or bad, the welds are.

I’ve attached a drawing of the front part of the frame, with red lines showing where the welds are. The two side pieces are mirror images.

Weld #1 is on the fireman’s side frame piece and has a visible crack, so it will need to be ground out and re-done.

Weld #2 is on the engineer’s side frame piece, and is where a bolt hole for the forward binder bolt is drilled.

Weld #3 is on both frame pieces. Note that the space between #1 and #3 is where the cylinder saddle fits.

Weld #4 is on the engineer’s side frame piece.

A couple of possible scenarios as to why these are there: 1) it was in a catastrophic wreck, and the whole front end of the frame broke off; or 2) the cracks developed over time, and probably not all at the same time, due to the bad track conditions it was likely operated on.

So, how serious is this in regard to restoration to operation? Is the frame going to crack elsewhere? Is there any way to tell for sure if the welds are strong enough to hold the frame together? I’m guessing that our track is in lots better shape than what the lumber company ran it on, so the stresses on the frame might not be as much.

I’ve talked to a few people about this, and, of course, their opinions have ranged from, “I’ve seen lots worse that are running fine,” to “Don’t waste your time and money on this, it will never work out.”

Anyone care to add their opinion?

Thanks.

Hi,
Are you sure about the location of cracks 1&3? I would expect them to start
from the 1/2 in. radius nearby.
As for the quality, the welds could have been made without preheating the frame so the next crack was built in.
I myself would prefer thermite welding for a cast frame, the way rails are "cast"
together using the mixture of aluminum powder and iron ore.
Kind regards
Jos Koopmans

Crack &3 only makes sense as drawn if there were a significant frame void or other defect in the steel. I concur that it "should" have gone through the stress-raising radius.

Please bear in mind that the correct alloy formulation for Thermite welding of a cast-steel frame will be different than for rail steels. Matt Austin will be able to provide precise metallurgy, including the allowance for alloy constituents 'burned' out of the mix during the casting process.'

I of course will mention laser keyhole welding, if you can have the service or loan of the equipment donated or provided at reduced cost for 'publicity'. (It would be excellent publicity for the unique advantages of the method!)

I would at least think about a jig that would hold the frame in correct alignment during pretreating, welding, and aftertreating, no matter what type of welding is used.

OK, you've heard from some very smart people about good and valid reasons why a crack appeared where it wasn't supposed to, and various exotic repairs.....

I'm going to be more practical, and suggest you do some testing of the general quality of the metal in the frame before committing to the project. It is possible that the frame itself is disposed to fracturing, in which case, you might want to reconsider repairing it for operation at all. If not, you may find some history showing a head on collision or something similar which could have been responsible for this kind of damage. It may also be worthwhile to do testing to determine if there are further voids or inclusions in the frames at which new cracks will be more than happy to appear and surprise you at inconvenient moments.

There are also some less exotic but also workable ways to repair a frame that is made of good, weldable metal that you can explore with the more advanced steel fabricating companies in your area. Controlling the flow of heat over time, percussion of hot metal, and other possible parts of the repair strategy will probably be more dependent on what those contractors in your area can provide than an academic ideal technique anyhow.

So, find out if the frames are going to be able to be made reliable before worrying about how to weld them. If your metal is good, then find contractors who do complex repair jobs in stressed frames and choose the best fit for your circumstances.

dave

My two cents:

If the “cracks” are cracks and not “breaks” (i.e. where the frame is in two separate pieces), what percentage of the frame is cracked in each case? Often, cracks partially through a member can be vee’d out with a grinding wheel or burr with no strength penalty since the there was no tensile strength in the crack anyway. Once the full extent of the crack is known, the best course of action can be chosen, from doing nothing more that smoothing out the vee if the crack disappears a short distance under the original surface to weld repair of the frame member, to addition of a doubler to the side of the frame member, to complete replacement of that section of the frame.

Cracks 1 and 3 are the most critical in that they could reduce thrust support for the cylinder block. Distortion due to a poorly planned weld repair could have the same effect in those areas.

Good practice dictates that a sample of the frame steel be taken and sent to a lab for analysis before welding is attempted so that a proper welding procedure can be adopted for the weld in that area. Per a retired chief metallurgist of Bethlehem Steel, the carbon content and chemistry of a cast steel frame can vary greatly from one end to the other of the same casting. Nominally, cast frames are made of easily weldable low carbon steel, but the builders were notorious for their carelessness in material control. We were faced with welding a cracked frame that when tested, contained .37% carbon in the area of the crack, requiring tremendous care in heat treatment before, during, and after welding.

It's great to see another practical steam thread on RyPN.

Overmod brought up laser keyhole welding (apparently also called laser-hybrid welding), a process I'd never heard of before. Wikipedia has a decent article on it: http://en.wikipedia.org/wiki/Laser-hybrid_welding

I gather from the article that this process might allow the cracks to be repaired without V-ing them out first (or at least reducing the amount of V-ing out required), which would be a huge savings in time and labor. The article does make the point that there is limited knowledge of the fatigue behavior of these welds, so it does sound like using this process would be a bit risky. The uncertainties Dave and Kelly mention about cast frame metallurgy would seem to add to the risk of using this technique for the crack repairs.

Whatever process is followed for the repairs, hopefully Jim can document the repair process and post it here.

You might also check with Lock-N-Stitch in Turlock, CA.

http://www.locknstitch.com/

Their crew does some big casting repairs world-wide. They also make some stitching products which might be useful in some cases.

I think the RGS # 20 that is being restored had 6 breaks in it's frame. The breaks were found to be repaired with railroad spikes as splice plates. The complete broken sections were taken out , new frame rails made and welded in with 2 instead of 6 repair welds. hocarsandtrains. James

I have had success with the Lock-and-Stitch product on small cast iron items, but the items I repaired are not structural.

They have used the product to repair flywheels, but those where rotating with a pretty constant load (not like on a punch press).

The uneven nature of the loads (track and piston) may stress the ability of that product.

I agree about getting some NDT info (how deep are the cracks, any voids nearby), wreck history (if possible) and some analysis of exactly what type of steel you have.

Preheating may be difficult assuming the cylinders are still attached, that's a lot of thermal mass to heat up.

Good Luck, Kevin

I would think the engine may have had some pretty good hard use just hauling and maybe a lot of hard couplings. Catastrophic damage would have shown elsewhere on the engine.
Hauling lumber and no brakes on equipment in switching and everything else sounds like rough use.
I would go forward and get it done for your maximum safety.

Interesting, I seem to recall an example of a flywheel repair at the locknstitch (tm) website a few (5-8) years ago. It's not there now ?

Anyway, the locknstitch stuff is very good for cast iron and aluminum (cylinder head) repairs where things are generally in a compressive mode (cylinder head torqued to an engine block). In a structural application where things alternate between compression and tension they may have some limits.

Their claim to fame is repairing cracks inside castings (cast iron specifically) where welding is impossible. They have a very nice tutorial about why you cannot successfully weld a crack inside a cast iron part. The strength of the base material cannot survive the forces from thermal expansion/contraction applied during welding. This is less of a concern for steel with greater compressive and tensile strength than cast iron.

Cheers, Kevin.

Have examined a number of smaller mining or logging locomotives that have had some very interesting repairs to the frame. I think frame repairs are as interesting as old boiler repairs. On some logging and small mining operations the repairs are clown scary. Last week or so I was allowed to examine for only a few minutes the frame on a narrow gauge 2-8-0 {from 1900}, that was stripped down to the bare frame. I would like to go back and examine it some more. What I saw in just a few minutes was fascinating. Extension added to the rear of the frame bolted on or appeared to be, didn't have the time to truly examine. Welds all over, some were build up weld, others appeared to be frame repairs. On a very small Lima 2-6-0 the frame repairs were atrocious from the welding that is exposed. Who is to know what else is hidden without a detailed exam?

It is truly educational to examine closely frame repairs or repairs that may need to be done. Many locomotives "fell in the drink". Some damage might be more stress related? Some of these locomotives were literally beat to death before retirement. Another thing to remember is most old frame repairs were done before electric welding came into it's own. So the welding might of been gas welded or if later towards WW2 may have been welded with the equivalent of coat hangers. Would like to see some detailed pictures of the repair area. Agreed another good thread on actual repairs and ways to go about it.

So any pictures available to us nut jobs who get off on this kind of work?

Regards, John.

John: Pictures coming in next couple of days.

Arc welding was developed in the 1890's. During WW1 ship hulls and aircraft were first welded. The first complete ship hull fully welded was in the 1920's. Mig welding came about in the 1930's. Most railroad back shops had large 300 amp carbon arc welders for mild steel and cast. One of the SP 4-6-2. locomotives had the frame preheated with halogen lights before it was welded. There are many possible types of welds that could have been done. hocarsandtrains. James

You're thinking of their drill-and-tap "stitch" products. They ALSO weld.

They are one of the few shops competent at welding cast iron, which is extremely difficult to weld, and you have a lot of jackasses running around saying they can arc-weld it with their nickel rods, which makes their abilities seem pedestrian. Read their site, they discuss at length how their methods are notably different from what almost anyone else out there is doing. WRM has sent a bunch of work there. None of it was ever stitched. It was all welded.