The Hawaiian Railway Society is currently restoring a wood passenger car built by the Oahu Railway and Land Company in 1920/21. The car was completely disassembled with drawings made of each part as it was removed. The frame is now being reassembled. New wood bolsters have been fabricated and new side sills installed. The original center and intermediate sills have been repaired using “West System” epoxies and one center sill spliced in accordance with the 1917 MCB “rules”. The center sill splice has the additional benefit of the epoxy not available in 1917.

The same center sill was found to require a splice at the extreme opposite end due to rot. This second splice in the center sill would not be allowable under the 1917 rules. It was decided to install a short splice using epoxy. The draft gear timbers would span the splice and be through bolted per the original construction. This decision was approved based on the modern technology now available, i.e. epoxy, and the availability of a short section of properly dimensioned scrap material resulting in cost savings for the project.
Unfortunately the added piece was not square to the horizontal surfaces of the center sill and dipped down about one-quarter to one-half inch. Attempts to straighten it using weight and time proved unsuccessful and when greater weight was used the sill developed a horizontal crack from the location of the splice as far back as the bolster.

The question now presented is one of safety. The crack in the damaged center sill can be excavated and filled with epoxy or a new section spliced into the existing sill inboard of the bolster as was done on the other end. We are seeking the opinions of those of you familiar with wood car construction and especially anyone who has done such work as to the safest course of action to repair the sill. Complete replacement is also an option but we would like to avoid the expense of a full dimension center sill forty-four feet in length plus shipping to Hawaii.

Jeff Livingston

Have you considered a metal reinforcement?

dave

Can you post a photo of the crack that developed and describe the service the car will be in when finished.

Jeff and I have had some private discussions…

The car in question is a wood underfame car, with 6 sills, wood bolsters, and separate platforms. The wall system is a basic post and brace with a king post truss over each bolster.

The Hawaiian Railroad Society started to disassemble and document the car some years ago, as it started to disassemble itself as the side sills both failed. I did an assessment and wrote a preservation assessment for the car on a visit in 2011. At that called for new side sills, end beams (sills) bolsters and truss or queen post beams. We anticipated some epoxy consolidation or splicing in the center and intermediate sills, so while this is more than expected it is not exactly unexpected.

I like the idea of spicing the sill in question between the bolster and queen post beam… it is compliant with MCB rules and practice, and gets rid of the damaged end of the sill. I would follow the MCB splice pattern, but would add epoxy, and likely sister the area with steel plates on either side through bolted across the sill… I might wait to add epoxy and make the repair rigid until the car frame was generally compete... In my opinion, trying to clean out and glue the failed sill end is trying a make do solution, and depends exclusively on modern epoxies.

They have the advantage of a car which is “very” disassembled, so the work will not require much (or any) additional disassembly and sill end will be the only original material lost.

Jeff can better answer questions, but it will see some regular operation, in short trains, on generally level track.

The Hawaiians have a number of members with extensive ship and shipyard experience and so some really nice work with steel and diesel electric locomotives… (they have 4 small diesels… all run, all look better today than they did 10 years ago… not many groups can say that) but they are sometimes concerned about decisions involving wood.

This is one of three wooden passenger cars in the collection. One, their “observation” car (No 64) is fully restored and well maintained. This car is a 2nd class passenger car, with an arch roof. The third was/is a 1st class car that also suffered from complete side sill failure, and has been disassembled and the parts stored to allow future restoration. Hawaii is not a easy place to keep wooden cars… it is wet with the rot that can bring, their location is near the ocean with the rust that it brings, and they have some of the nastiest termites found… the OR&L Co maintained a fumigation building do deal with pests.

Randy

Gentlemen,

Thank you for your input. The photo shows the angled splice line and the repairs to the crack that developed on the left side. The original epoxy securing the splice actually gave way under the pressure used in the straightening attempts.

Jeff Livingston

My inclination is to second Randy's suggestion about where and how to splice in new timber....and note that the epoxy isn't failing, the wood adjacent to the epoxy is failing if I'm understanding the situation correctly. Weak wood will fail next to a good epoxied joint or elsewhere. It seems you have ample evidence of this end of this timber being weak.....and it is possible the difference in strength and resiliency between the epoxy and the weak wood could provide a focus for future failures.

dave

I'd be inclined to splice in a short length of new timber, but to use a stepped joint rather than an angled one. Mainly because it's a bit easier to keep everything square and level. As you attempted here, I'd use lots of epoxy and would be sorely tempted to sandwich the joint between two fairly long steel plates with a decent number of bolts.

Provided the crack that developed when you tried straightening the beam is in solid, clean, dry wood, I wouldn't be too bothered by excavating and filling with epoxy- just ensure the steel plates extend past that repair.

This doesn't appear to be a highly visible location, so the reinforcement shouldn't be much of an issue.

Steve Hunter

One issue I always take into account when planning wood car repair is the use... if the car will be stuffed and mounted, you don't have to address the dynamic forces from train operation, particularly the draft forces...

Since this car will see use, I think about using railroad practice instead of just gluing it back together... and railroad practice was a splice between the bolster and needle beam, with a z joint and a specified bolt pattern based on sill size (MCB practice)

Of course the railroad's didn't have epoxy available...

Adding epoxy to the MCB joint should make it better, and steel plates even more strength (and I have found wood frames reinforced with steel plates, making it railroad practice as well, just less documented railroad practice...) but with epoxy you have to consider whether the repair might be too rigid and therefore brittle and more subject to breakage. And in this case, the repaired beam was rigid and brittle enough to break when they tried to pull it into line...

When I use epoxy on wooden structural members I try to only consolidate or repair a part (like one sill, splicing, or adding dutchmen) making sure that all original joints are free, keeping the frame flexable in the ways it was designed to be.

Randy

I am not a big supporter of reenforcing wood timbers with steel plates. The wood and steel have differing strength and elasticity and will not share the load. If the connection between the wood and steel is adequate to transmit the forces into the steel, then the steel will carry all the load. Otherwise the joint will loosen up and wood will carry all the load.

The question of the epoxy's impact strength is a good one. I would be interested to know which filler you are using in the epoxy. Another problem with the epoxy is it deteriorates with time. It may have a structural life of twenty years. These would be good questions for the West application engineers.

On the long split I would suggest you add two lines of large vertical through bolts. The holes should be sized so the bolts have to be driven in. This will help prevent additional splitting and should act to carry the loads in the timber from one side of the failure to the other. The bolts need to be large not for their strength, but to give the wood enough cross section the carry the load. Do not put the bolts side by side, use a stitch pattern.

As far as is the car is safe to operate, I would think so. If this joint fails, there should be a slow deterioration of the joints, not a sudden failure. Many category one hazards have been converted to category three or four hazards by scheduling regular inspections.

If you splice in a new piece of wood with a long horizontal splice, I would recommend the use of trunion rings to reinforce the joint, in addition to the epoxy. The important issue in splicing in new wood is to find wood of sufficient quality to use as sill timbers. Finding good wood is probably going to be the toughest part of the whole project. I have the most luck with finding large old used timbers, and resawng them into what is needed. We find that wood cut prior to WWII is best. Due to the pressures of the war, a lot of wood was used that was considered to be temporary and it has not gotten any better with age.

My personal experience where wood is starting to fail is to soak the area with Git- Rot. It is a very thin epoxy that soaks into the grain and fills any tiny cracks. How long it will last is unknown to me. I have seen it last for 20 years in a wooden boat.

Git-Rot is available at most marine chandleries.

I donno, there was certainly enough wood truck beams and bolsters designed with iron "fitch plates", the idea being to combine the tensile strength of wrought iron with the compressive strength of a large wood section.

That being said, I see the ARA Mechanical Division (former MCB) standards for splicing wood sills, adopted 1911, as revised 1919, calls for reinforcing the splice with a wood member sistered on the side of the splice, this member to be the same depth as the sill, 6'-0" long, and either 2" thick (if oak) or 2-1/2" thick (if pine or fir). Since most sills are 4"-5" thick, this is essentially increasing the cross section by 50% through the spice, and should have similar properties of shrinkage and flexure.

I stand by my previous advise to splice between the bolster and needle beam, but I have a background concern about all of this...

I don't believe that any of these options have ever been subject to a calculation or review by a structural engineer... (If they have been, I would love to see that report)

Instead we are relaying on a traditional railroad approach... the design is traditional, the splice is traditional... Steel sistered to splices or to sills is traditional... These are techniques which evolved with practice to become MCB standards. the evolution consisted of trying various things, fixing what failed, retaining what worked...

Of the solutions we have discussed, only epoxy is a new player...

More than one educated person (aka holds a degree in engineering) have brought up the issues with steel and wood and how steel was attached if you were reinforcing the wood sill... suggesting that in addition to bolts you you should use liquid nails or equivalent construction adhesive to tie the two together and better transfer forces.

We are dealing with traditional seat of the pants solutions... but fewer and fewer of us have the first person experience that old Master Car Builders did... we have the advantage of being able to study their solutions, but the solutions are still theirs, and sadly their voices are not part of the discussion...

Randy

Gentlemen,

Again let me thank you for your input. Mr. John DeYeso has done all the work on the frame and both he and I have discussed the situation at length. Following the recent repairs to the center sill section beyond the bolster it is quite improved and a potential permanent solution may be at hand. While Randy is quite correct that we do not have a MCB to consult we do have their legacy. Mr. John Hughes, the MCB of the Oahu Railway and Land Company. left us quite a bit of information in the construction of parlor car No. 64 which has an observation platform almost one third the length of the car. Studying the construction of parlor car No. 64, (1900), coach No. 2, (1910), and coach 57, (1920/21), all built under the supervision and design of John Hughes give us an extraordinary amount of information. I will attempt to sketch the proposed repair and post it for comment as soon as possible.

Jeff Livingston

For Dave Johnson,

I'm not familiar with "trunion rings", could you explain please.

Jeff Livingston

Jeff, trunnions rings were used in heavy timber construction to key joints that were in shear. For instance if the joint was to be clamped with 5/8" diameter bolts, these bolts have a fairly small cross section and may tend to split the timbers loaded in shear. To address this problem trunnions rings were installed around the bolts to increase the bearing area on the wood. The ring might be two inches in diameter with 1/4" wall and three inches long. A special cutter, something along the line of a hole saw, would be used to cut 1/4" wide grooves on both faces of the joint piloting off the bolt holes. The rings would be installed in one face of the joint with about half the length of the ring projecting above the face of the joint. The projecting ring engages the grooves in the mating face. Then the bolts are installed. The bolts are clamping the the two faces together while the rings provide a large bearing area to handling the shear forces. This same joint could be assembled using epoxy adhesive as an additional securement.