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Steam & Excursion > Roundhouse Inspection pits and frame binder-bars

Date: 02/02/24 12:22
Roundhouse Inspection pits and frame binder-bars
Author: wcamp1472

A crucial aspect of loco frames are the frame binder-bars.
The binder bars are stout bars across the two 'jaws' either side of
the driver axle and its lubrication system.

The journal box is open at the bottom, but does have a means of 
supporting either a spring supported grease-block, or a similar arrangement
used the keep oil lubricants up against the turning axle.

There are two surfaces that are critical to be supplied with reliable 
lubrication application systems.  There is the rotating axle ( cylindrical) surface,
distributing the spring-load evenly across the journal area, and the surface
is the inside smooth area of the drive hub.  

The driver hub is a disk on the inside face of the driver that rubs against a brass
wearing-surface, called "the hub-liner".  The hub liner is a matching semi-circular
bearing surface,  that matches the area of the drive wheel's flat hub.  

However, when travelling down the R-O-W, the hubs DO NOT continually rub
against the hub liners.  The hubs and liners only rub against each other while 
navigating curves..... otherwise, the axle 'floats' between the hub surfaces,
in a non-contacting manner.

Lubricating the hub liners is a critical aspect, and RRs had various methods to 
provide lubrication to this vital area.  So you may find several variants on how 
hubs were lubricated.

Axle, plain-bearing, cylindrical surfaces were lubricated by conventional 
grease-blocks, or by oil cellars.  The grease block system uses a metal screen
on top of the grease block. The screen is curved to match the axle's curved surface.
The screen's function is to control the rate that the grease block feeds grease 
to the axle.  The grease block is made of a tough, paraffin block that only lubricates 
at warmer journal temperatures.  The metal screen ensures that the grease block
wears in a uniform and even pattern.  

The grease blocks can last for thousands of miles.  However, in today's world 
purchasing suitable grease block material is a very hard task, and a lot 
of operators are converting over to oil-axle lubrication cellars.

SP was an early user of oil-cellars in locomotive driver axle lubrication schemes.
SP had hundreds of various kinds of locos, all riding on grease block lubrication.
And, under-frame inspections typically revealed one, or more worn-thin grease
blocks.   So, new grease blocks had to be applied. it could take up to 1/2 hour to 
replace a single, worn grease-block.  And it's reasonable that 25% of the loco 
fleet could require one, or more fresh grease blocks.  The change-out time
was extensive, across an entire fleet of locos ---- from 0-6-0, to 4-8-2, to 4-8-4,
and to their 8 driver-axle cab-forwards..

So, with about 1/3 of their fleet 'down' for worn grease blocks, SP set out to
switch over to oil lubricated driver axles.  At the time, all freight car and passenger 
car axles were lubricated by oil cellars.... millions of axles across the country.

They were very successful in developing quick-refill, oil cellars.
[ I'm not familiar with how SP lubricated their driver hubs, when using 
   oil cellars.  Others can be more informative]...

Anyway, let's get back to the 'pedestal jaws' of loco frames...
The driver boxes are steel castings that slide vertically in the loco frames.
Each axle has journal boxes at its 2 driver wheels.  The journal boxes 
have wearing surfaces front and rear sides of the axles, as well as vertical 
edge-guides that constrain the allowed, side-to-side movements of the axles.

The vertical frame members on either side of the axles, front and rear,
are bound together at the base by binder bars.  There are rectangular
blocks at the bottom of the pedestal 'jaws', and the binders lock the 
frame securely under the axles.

It is crucial that the binder bars are strong and kept tightly secured by 
large 'binder bolts' extending below the frame rails and through the 
binder bars.  Large hex-nuts are used to keep the binder bars 
securely tightened.

However, every trip loosens some of the binder bars.  These get re-torqued 
by machinists with heavy-duty binder-wrenches.  A characteristic of modern 
loco frames is that the blocks that the binders hold so tightly, will wear with 
loosened binder bolts and hauling heavy loads.  

The rear frame binder blocks have a taper on the back side of the binder 
blocks.   The front and rear edges of both the binder bars and the frame 
'blocks' get worn from the constant pounding.   If not corrected, the binder
blocks could be drawn, up & tight, but allow the axles to beat the pedestal j
jaws.... so, a way to determine when the binders have 'bottomed' to the frame 
rails was incorporated.

The frame blocks behind the drivers, have a tapered rear edge, and the binder 
bars have a matching taper.  As the binder bolts get routinely tightened,
then pounded loose, the slap in the binders wears them.... and when 
re-tightened, the worn taper faces, allow the binder bars to be drawn closer 
to the bottom of the frame rails.

When, over time, the binder-bars are worn, eventually the tapers 
will have also worn --- eventually the binders will 'bottom' against 
the frame.   When machinists see that the gap between the bottom of 
the frame rail and the top surface of the binder has  narrowed, or has
closed-up and tight against the frame rail, the machinist will apply a replacement 
binder-bar with restored tapers, so that the gap will be re-established,
and the binder can be drawn-up, and the frame tight, again.
With a fresh 'gap'  ( between frame-rail & top of the binder),
of about 1/2".

The worn binder bars can be restored to spec, by adding new steel by
autogenous welding, then re-machined to restore the battered taper.

So, after every trip, the binders will have to be re-tightened...a laborious,
repetitive task.  It's one of the tasks which is vital, but also hastened 
the demise of steam loco fleets.


( Not proofed, yet).


Edited 1 time(s). Last edit at 02/02/24 12:23 by wcamp1472.

Date: 02/02/24 14:32
Re: Roundhouse Inspection pits and frame binder-bars
Author: Frisco1522

Wes, I'm a little confused by your description of frame pedestals, shoes and wedges and binders.  I don't have any drawings handy but pirated a photo of SP 786 frame to illustrate.
The binders are bolted to the bottom of the frame.  There are tapered slots on the top of the binder bar that are drawn up to machined bosses on the bottom of the pedestal opening on the frame.  On 1522, there was never any adjusting done as they were drawn up tight into the tapers, double nutted and locked.
The shoes had a straight front wear surface that rode on the inside of the pedestal.  The wedge, on the back of the pedestal had an adjusting bolt on the bottom which went through a hole in the binder and when clearance between the box got excessive, the wedge was drawn up to adjust it back to being within clearance specs between the axle box and frame.  I think that is what you're referring to in your post.  Ours never got to the "box pounding" state.  We would check the play with the engine steamed up, brakes set up full, open the throttle and work the reverse lever back and forth. You could observe the movement of the drivers/boxes and determine if it was acceptable.  Too snug and the box would stick in the pedestal when it heated up and the engine was working.  We would adjust the wedge bolts "flat by flat" until we were satisfied with the clearance.
The binders provided rigidity to the loco frame.  I always believed that any time the engine was off the wheels that the binders should be on all pedestals before the engine sitting on cribbing or jacks.
You're correct that good grease like Texaco Hi-Tex 8 is long gone.  If we worked over 1522 today, I would lobby for the oil feed system being used on some engines today.  Run cooler and eliminate the grease cake pain in the ass.
I'm older than dirt and hope the explanation makes sense.

Edited 1 time(s). Last edit at 02/02/24 14:37 by Frisco1522.

Date: 02/02/24 14:35
Re: Roundhouse Inspection pits and frame binder-bars
Author: HotWater

I always thought that those were called "Pedestal Caps".

Date: 02/02/24 14:46
Re: Roundhouse Inspection pits and frame binder-bars
Author: callum_out

Yup, that would be my recollection as well.


Date: 02/02/24 15:37
Re: Roundhouse Inspection pits and frame binder-bars
Author: wcamp1472

In service the bolts securing the "caps" can be 
pounded loose.  The key is that space between the flat top
of the caps, and the bottom of the main frame.

If you're regularly checking for tightened fastenters, that's a good thing.
Many of today's trains are less stressful on the frame components,
so they may not need frequent adjusting --- to keep them tight.

My experience was that we needed to frequently check to see
how many 'flats' were loose.  Some trips maybe some, other trips,
none were loose.

So, if you're checking, that's a good thing.
Some crews never check things like that.


Edited 1 time(s). Last edit at 02/02/24 15:46 by wcamp1472.

Date: 02/02/24 17:04
Re: Roundhouse Inspection pits and frame binder-bars
Author: Elesco

As a long-time aircraft and spacecraft structural engineer, with zero railroad experience, I vote that Frisco1522's response makes complete sense.  Clearly the binders/pedestal caps are an integral part of the frame, and pulling them into tapered surfaces is the only way to get joints that won't work loose.  Without them, bending loads applied to the frame would be concentrated in the upper frame members above the pedestals, which could be easily damaged.

And, as Wes says, having a gap between the horizontal surfaces of the pedestal cap top and frame bottom is necessary to be assured that the tapered surfaces are fully loaded.

Below is an assembly drawing from the 1922 Locomotive Cyclopedia.  Note the bracket and hole for the wedge adjustment bolt.

Date: 02/03/24 08:46
Re: Roundhouse Inspection pits and frame binder-bars
Author: Frisco1522

I think we're talking about two different things.  We always had a tight joint on the binder/frame fitting.
I was speaking more in relationship of the shoes/wedges which did require some tweaking from time to time.
There was such a thing as wedges that stayed in adjustment, known as Self Adjusting Wedges.  We didn't have these on 1522.

Date: 02/03/24 09:43
Re: Roundhouse Inspection pits and frame binder-bars
Author: wcamp1472

The original concern was explaining the necessity of a 
slight spacing between tops of the binders/caps and the loco frame.

In service, the caps wore at the tapers.  It is important to maintain tight binder-nuts/bolts.
If the fasteners get loose, the allowed pounding batters the frame tapers, in
a very short time.

That loosening tendency, and subsequent re-tightenings eventually draws the 
frame and binder-closer together.  It is bad-news when the space between the 
top of the binder-bars fits tightly to the frame ---- the bars continue to get worn,
and efforts at "tightening" stretch the anchor bolts, and with enough force, 
the frame bolts will be stretched and broken.

The small gap is crucial to fame and binder integrity. When almost closed,
replacement binders are required to restore that 'tell-tale' gap.

At the 'shop' worn binders were built up with new steel layers applied 
with stick-welding, and re-machined back to 'new' standards, ready for

If you have no gap, any further attemps at tightening will simply
stretch the binder bolts....and eventually the bolts will break --- 
either over the road, or the next attempted re-torque attempt.


Date: 02/03/24 23:45
Re: Roundhouse Inspection pits and frame binder-bars
Author: Elesco

Below is an Illustration showing desirable fit between the binder/cap and the bottom of the locomotive frame.  When the #19 binder/cap is pulled up hard against the bottom of the frame, usually by 4 bolts (not shown), contact is between matching tapered surfaces in grooves on the binder/cap and protruding lugs on the frame.  In order to assure these tapered surfaces are tightly pressed together, there needs to be clearance between the horizontal surfaces of the binder/cap and the frame, as is shown in the illustration.

This illustration is from a patent for an automatic driver box wear compensation device.  This involves wedges #20 and #21, which are not tight, but are adjusted to maintain adequate clearance with the driver box so it can move up and down freely as allowed by the locomotive springing, but not so loose as to allow impacting or pounding due to oscillating horizontal loads from the side rods.

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