sTEAM lOCOMOTIVE SIDE ROD CLANK

First, let me state the famous quote from MANY a railroad shop Machinist from the days of steam: "It is always better to HEAR the rods, than it is to SMELL them!".

The clearances in steam locomotive plain rod rearings, i.e. NOT roller bearings, is quite generous in order to allow room for the grease lubrication as well as expansion from heat. These clearances are generally in the measurements of 32nds of an inch, instead of thousands of an inch for internal combustion engines. 

Plus, if quartering is not extremely precise (and don't forget driver to driver spacing as the driving boxes move up and down) a little slop prevents driver lock-up or rod breakage.

A video I have on the East Broad Top RR  explained the clanking noise as slop in the bearings which, I guess, was excessive due to wear.  Older auto engines ran many miles with  worn rod bearings too.

I would have never dreamed that there was that much clearance in the side rod systems on a steam locomotive. I do remember seeing the stick grease that was used, not only locomotives, but on equipment that I worked around in my early days in the refinery where I worked. I never looked at the grease fittings, but I figure they were the button type. Well thanks for the intelligence improvement, still hard to be believe that much clearance. Guess that's why they always shopped them to checks these things out, after a run, or at least a refuel/water, and a good shot of lube, until the fire was dumped, and boilers washed out, and smoke box cleaned, along with a multitude of other maintenance items. 

Hot Water, did you have to change the oil tips very frequently when firing with oil, or was your all's system pretty clean, with exception of switching filter strainers?

There are no such things as "oil tips", nor "filter strainers" involved with oil fired steam locomotives. There single large burner is about 4" wide, with an opening about 1" high, and directly underneath that "port" where the oil flows out, is the slot for the steam atomizer (the slot is as thick as a hack saw blade, and is full width of the burner port). The oil is gravity feed from the tender (except on SP cab forward locomotives, where the tender was pressurized with about 15psi of compressed air), to the firing valve mounted below the Fireman's side of the cab.

Remember that originally, "oil fired" steam locomotives used Bunker C, which had to be continuously heated to at least 150 degrees F, otherwise it was simply as hard as road tar.

They clank to this day

At :23 here: ( a bit tough to hear with the wind and whistle noise but its there, not my video BTW)

On the EBT there is a stretch of track beside a pasture that is a favorite rail fan spot and you can hear the rod clanking like crazy. As was explained, the Strasburg Shop  did a low cost bearing job for EBT and helped tighten things up. I have been through the Strasburg Shop about 3 times and a great place. Beautiful work, for sure.

Hot Water, have never been the remotely close to a full size oil burning locomotive, with the exception of the 3985, when it was in Huntington, Wv years ago (Santa Train). When I met Steve Lee @ the Huntington Engine shops, he said they were changing out the oil burner, and replacing a lubricator on the right side of the engine. The fire was out of course, and the boiler was ambient.

I wondered how their oil firing was set up, and always wished that I would have gotten Steve to show me this system.

Good Movie RickO, and Kelly Anderson, great post, and very informative, plus I never thought of the drive wheels as a crankshaft, but thinking about it, you are correct. I'll look at them in an entirely view here forward.  With those clearances, the weight of the rods, plus all of the axiel movements, I understand where the clank/clanks come from and why! I never noticed the difference in the running noise when around the J611, but everything being roller bearings, probably nothing there at all unless, a bearing would fail. and very noticeable, if it spit some rollers out of the races! .......Thanks again guys, very good info as always, from you guys..........Brandy

The need for "loose fits", relative to automotive engines, is understandable.  But where are the corresponding loose tolerances located when rods are converted to roller bearings?  Surely the requirements for loose tolerances still remain?

Tony

Thanks for posting (my video)!  I always wonder why I upload what I upload, glad it's getting watched from time to time.

I'm not surprised at all by the 614 making more noise when it was older.  I watched the break-in runs of the 765 back in 2005 after the restoration. When she would go past a crossing the rods never even made as much as a whisper of noise. Now you can hear them pretty good in that video. It's been almost 10 years and she's getting some wear. I wonder if the cutoff setting has much effect on rod bushing wear...

Timken introduced roller bearings into steam engines and it was pretty well thought out process plus they ran a demo engine. Don't forget, bearings are a wear item that is why they are there.

I once worked with an 80 year old guy who once worked on SAL steam.  He told me that the holes for the knuckle pins (crank pins?) had to be 1/4 " larger than the knuckle pins or they would "spall" inside.  He told me one of his first assignments was to drill holes in the siderods.  When they rolled the engine out of the shop the foreman came running up and shouted for them to stop moving the engine.  He asked McGee how much tolerance he put in those holes he ordered the engine back in the shop.  He told McGee that he knew something was wrong because the engine was so quiet.  Thus is old railroad lore passed on.   Odd-d

There is a sound clip of an Pennsy I1SA coming down around Horseshoe Curve running lite and you can hear the side rods clanking as plain as day.

I think this sound clip is from Semaphore Recordings, Sounds of the Horseshoe Curve

Mark Strittmatter

TCA#14-69917

Indiana PA

Yes, it does.

If the cutoff is set too short, the machinery will grumble about it because there is not enough steam left in the cylinder at the end of the stroke for proper compression. This "compression" occurs at the end of the stroke when the piston reverses direction. If the proper amount of  steam is left in the cylinder when the exhaust port closes, it is compressed at the end of the stroke and "eases" the piston to a stop and starts it moving in the opposite direction.

If the cutoff is too short, there is little or no steam left in the cylinder when the exhaust port closes. Without that steam in the cylinder, there is nothing to compress at the end of the stroke to ease the piston's change of direction. The result is the machinery makes noise - a little clanking and banging in step with the rotation of the wheels. Each clank and bang takes a tiny bit of life out of the bushing.

Yes, the 765 was totally quiet when we first put her back on the road in 2006 after the overhaul. She is making a little rod noise now, but she's entitled. Those rod brasses have somewhere around 40,000 miles on them now! But the tiny bit of rod noise she makes now is nothing compared to what she sounded like in 1993 when everything in the running gear was completely worn out. I'm sure somebody will find a clip on YouTube. 

Rich, what would be the expected life cycle on those before replacement would be considered?

100,000 miles.

But the tiny bit of rod noise she makes now is nothing compared to what she sounded like in 1993 when everything in the running gear was completely worn out. I'm sure somebody will find a clip on YouTube. 

At  9:23.    Sounds like the background factory sounds on Billy Joels "Allentown". You can a-l-m-o-s-t hear the rods over the whistle