Steam & Excursion > East Broad Top returns EBT 16 to service

Rockhill Furnace, PA — Steam has once again returned to the East Broad Top Railroad after eight months of extensive repairs to its historic steam locomotive, No. 16. Built in 1916 and now 108 years old, this engine is set to resume service as the primary locomotive for the rest of the 2024 season.

Link to official press release:
https://ebtfoundation.org/steam-locomotive-returns-to-east-broad-top-schedule/

/Ted

Great news. Congratulations to the EBT crew for a job well done. Here's wishing them a great fall and winter season. Ross Rowland

Cool!

Unfortunately, they report #16 experienced a "minor but persistent issue" during its 11 a.m. excursion and is being withdrawn from service for the Labor Day weekend. Scheduled service will be continued using their diesel.
https://www.facebook.com/ebtrr/



Edited 1 time(s). Last edit at 08/31/24 12:37 by Cumbresfan.

Hey Plywoody, take a chill pill.  It's a century-plus old steam locomotive and you know darn well **** happens; particularly right out of the shop.

They posted this morning that a driver bearing was running warm, and they put her back in the shop to fix it.  It's not that big a deal.

Mary McPherson
Dongola, IL
Diverging Clear Productions

Plain bearings at loco drivers,  can be expected to "run warm"; that's a characteristic 
of grease-block driver axle bearings.

There are oil-lubricated driver axle bearings.  
That tend to run cooler, and there are some current operations 
that are converting/up-grading to oil-lubricated driver bearings.  

The challenge is the adequate lubrication provided at the driver-hubs.
The 'hubs' are the vertical, circular surfaces that come in contact with the 
brass hub-liner of the drivers' journal-box  ---- continuous hub-liner contact only
occurs while navigating curves and switches... most of the time the hubs do not
rub against the hub-liners.  In the old days, it's the major purpose of the 
long-spout oil cans:  at every station stop engineers would dribble valve oil
between the driver hubs and the driver juounal-box's: hub liner.

A  characteristic of grease-block lubricated bearings is that as axles  warm-up,
more heat-softened grease is brought between the rotating axle and the journal brass...
sort of a self-regulating way of increasing the amount of lubrication.

 A critical step when fitting new, or recently bored crown-brass, is to with a sharp
scraping tool, is to scrape-away the new brass at the fresh edges.  
Newly machined brass and its un-treated edges can act tike wipers and peel-away
the axle's oil-film, as efficiently as a windshield-wiper.

The entire length of both sharp edges must be scraped to a width of 1/4" or more,
to form a wedge-like area to spread the lubrication across the whole axle face.
The lubrication can be either grease-block or oil-fed. 

The secret with 'plain-besrings' is that the oil film must be 100%,  and 
it separates the rotating axle from the smooth surface of the brass.
Any tiny area of metal-to-metal contact will cause local heating, and 
eventually the whole assembly gets overheated and ruined.

If heating starts, the surface of tte "brass" heats first.  The surface area,in contact 
with the axle, heats quicker than the entire brass-block --- since heating necessarily 
involves expansion of the brass, the area in contact with the axle necessarily contracts,
tighter, onto the rotating axle --- further tightening the brass & its fit, and reducing the
lubrication area .... increasing the metal-to-metal contact area.  
This heating process increases over time.

The axle, being 12-inches or more in diameter, is slower to heating-up...but, remember
that the brass coves 50% of the axle's surface.  Soon, the axle heats-up, and it too
MUST expand, thus, tightening further the fit between axle and brass.  
Heating-rate eccreases, and the interference area becomes extremely tight and HOT.

The best way to reduce break-in problems is to bore the brass diameter MUCH 
wider than the diameter of the axle.  Together with edge-taper scraping, as above,
and the much larger bore of the brass, will allow for ( invariable) temperature
expansion of both the "brass",  which contracts tighter to the axle, and the axle-heating
which causes the 12" dia. axle to expand.  The two "heating" components of the
bearing surfaces MUST be of greater clearances,  when each is at cooler, room or,
atmospheric temperatures.

Greatest amount of metal expansion occurs between 150-F and 450-F.  
On both axle/bearing components, that can a loss of 1/4" of what had been 'free-play" 
at room temperatures.

 Driver bearings want to be very loose, when first fitted-up.  The break-in period
is crucial as the two 'raw' surfaces polish-to each other at a high-shine.  
Once the two surfaces 'marry to each other' , 500 or so miles: you will get a couple of 
hundred, thousand miles of service... As long as the two surfaces stay well lubricated.  

Years of sitting around, on display, allow driver axles to rust and pit on the exposed 
areas, bare of an protecting lube-film.  Oil lubricated bearings go-dry quicker than
axle-grease lubricated bearing areas.

What's concerning is any axle bearing that is running at distinctly higher temperatures,
compared to other axles on the same loco.  
There's several common remedies, mostly varying by persons' personal favorites.

So, they have the shop facilities and the people to remedy bearings that are tending
to run warmer than other bearings, on the same loco.
Sometimes, it's a temporary condition, others may require simple remedies.

​W.

 



Edited 4 time(s). Last edit at 09/06/24 07:43 by wcamp1472.