So the new observation car at D&S has roller bearings. What is your opinion? Should D&S switch the fleet to roller bearings? What is the nostalgia/operational trade off?

IMHO nobody's opinion is worth considering apart from that of the management at D&S (this one included). It's their railroad and only they know what is best for their operation.

dave

Maybe they could do conversions and keep the journal box covers. We did that on our Aux water car.

It's a NEW car, folks. Roller bearings make sense for that. Convert the fleet? Does not make any $$$ or sense to convert when everything is working correctly. If there were service or reliability problems, then we would have already seen a move toward RB's.
IMHO!

I was thinking maybe the reduced resistance would allow longer trains (more revenue), or conversely reduce wear on the locomotives.

At low speed is the difference trivial?

It does make a large difference on my miniature train.

Heck yeah. New is better. Roller bearings, ditch lights, concrete ties, HEP and AC traction motors under Tier 4 diesels!!

But seriously folks... I suspect rolling resistance is NOT their ruling factor.

My lay understanding, acquired far too long ago to be able to quote sources... below 10 mph, roller bearings are slicker, but plain bearings become slicker as they gain speed. Makes sense if you think about it, since the roller bearing is ready to do its thing all the time, but the plain bearing needs some speed to get the oil flowing.

As for economics, the roller bearing paid for itself in a year of paying a car knocker and oil to keep the plain bearing topped up. For museums, the roller bearing is also lower maintenance, and less likely to have a problem, but you're really out of luck if an exotic roller bearing fails.

The comment about "exotic roller bearings" is the reason Pennsylvania Trolley Museum re-engineered the roller bearing trucks that came with our ex-Rio open car as acquired in 2006. We had to regauge the trucks in any event to be able to use the car on our 62.5" gauge track. Upon discovering that the bearings were of UK manufacture c.1935 we had Lyons Industries, doing the truck rebuild for us, source new bearings of current sizes as part of the rebuild. This will hopefully assure a long service life for these trucks as this car sees a lot of use.

Another PTM project is the restoration of West Penn Rys Cincinnati "Curved Side" car 832. These 12 cars had solid bearings as originally built in 1930, but by 1935 WP was converting the whole group to roller bearings. As part of the conversion WP added an axle ground brush to the trucks, to minimize the amount of return current passing through the bearings. As these bearings were a standard Timken number, still readily available, there was no problem finding replacements. In this case it was Brookville Eqpt. Corp. doing the truck overhauls for PTM under a Federally funded Transportation Enhancement grant. The car is now undergoing finishing work at PTM and is expected to enter service in late 2013.

Roller bearings are fiscally responsible, the cost of an appropriately sized roller is nominally the same cost as that of a new solid bearing once you factor in material, casting, babbiting and machining. Now lets take that a step further, once you convert to roller one no longer has journal pads or oil to worry about.....less expense yet. Then consider that a roller bearing (especially in low speed/low load service as it would be in durango) will out last a solid by atleast 7 to 1(assuming a properly maintained solid bearing). Granted, one has to open up the back side of existing boxes and shave down the axle to 1/4" below d&rgw original diameter but when an operation has a machine shop like durangos' it's not that difficult.
Add it all up, in the case of a for profit operation which makes more sense?

Cheers, Jason

That makes sense if you're building new stock. Otherwise you've got a fairly significant engineering project which CAN go wrong, and often DOES go wrong.

Also, you have a downgrade in terms of maintainability and early warning of problems. Plain bearings complain for a long time before starting to cause serious damage (other than to babbit and waste). Clean up the axle end and change the brass, you're back in business. Roller bearings fail fast and without notice, and steel-on-steel damage starts to happen immediately. You've got a trainload of people who will tell you about a failing plain bearing... how will they detect a failing roller?

And now your bearing has failed in the middle of nowhere... how do you remediate the problem in the field so you can get the car back to the shop? I'm pretty sure you can't field swap a roller bearing, nor does it have enough failure margin to limp it home anyway. Whereas brass is a lot easier to change, we know that lol! The big railroad approach, I believe is to swap the entire axle set or truck in the field, but they're dealing with highly standard freight trucks. You got a spare axle set or truck for every piece of equipment you own? Does the equipment lend itself to that type of field swap? /skeptical

Oh fer chrissake.......

STARTING resistance. Once rolling it isn't as different. Diesels can start loads they can't pull, steamers can pull loads they can't start. Starting resistance is a sensible criteria to consider for steam powered railroads to maximize capacity.

The adaptation to roller bearings is an established, robust and completely known quantity and whatever actuarial information is required to make a rational decision is available. Narrow gage roller bearing trucks are in wide use on other lightweight transit systems in many parts of the world. D&S is essentially a lightweight transit system operating to provide tourists scenic transportation between entertainment destinations. Again, rational criteria.

Of course, anything can be done badly but I don't know enough specifics to assume the very qualified decision makers at D&S would screw it up or to presume to offer any worthwhile opinion as to its likely success. Neither does anybody else posting here that isn't involved.

dave

You probably won't see any serious efforts at converting an existing fleet because of the opportunity costs involved. However, for new equipment (such as the WP&Y) you will see plenty of roller bearings for the reasons that Jason pointed out.

There is also institutional conservatism as work for the reasons also outlined (catastrophic failure, equipment standardization, lack of shop equipment/maintenance practices/etc) that will present itself until a railroad has the opportunity to make a large enough change in their wheel bearing inventory (purchasing new equipment) that converting an entire fleet to roller bearings would be a cost effective capital outlay.

IOW, roller bearings may be a solution in search of a problem. How often do any of the large plain bearing operators (D&S and CT&S have hot bearing issues? If they aren't or the problems are addressed through periodic maintenance, than rollers may not enter into the equation at all.

Note that the car was built and DONATED to the D&S. It may well be the only roller bearing equipped car in the fleet--anybody know?

This is a good issue to study, especially as the current inventory of narrow gauge trucks shrinks.

Is that all they do?

What about preserving the authenticity of historical narrow gage steam railroading so riders can experience it as they are transported between their entertainment destinations?

WP&Y completed the conversion of their entire fleet of passenger cars to roller bearings in 2010.....after the 2nd to last on brass caught fire!

TH

The technology is a stage set for the experience. This is a historically themed and branded tourist attraction, not a preservation project. The preservation is incidental to their purpose, not the purpose itself. I'm thrilled that they are proving that - at least with enough other stuff like scenery to look at - it is worth maintaining the historic character as a vital component, even if it isn't dead-nuts authentic down to the rivet heads.

I'm not sure any operating museum - not to mention tourist railroad - has not compromised with absolute authenticity for the sake of programming. The success of D&S should be the envy of many of them.

dave