Nostalgia & History > MU hoses question

Recent photos of mainline Diesels seem to always show a full complement (3 or 4) of MU air hoses to each side of the coupler. I'm guessing that a full set of functioning, in-date hoses is one of those things that must be inspected before leaving a terminal. Should there be a need to add or rearrange units somewhere down the line, having those hoses in place could come in handy.

The question comes up when I look at historic photos (for example, the ALCO alligator photos on the Utah Ry thread below), and many times I see a brace of hoses on one side of the pilot only, with pipe plugs on the other side. Assuming the railroad is big enough to commonly require units in multiple, I'd think one or two calls every week to go out with the wrench & slap on some missing hoses would wear thin after a short while.

Or was this accepted practice at one time?

Was it up to the shop forces to do as they saw fit in this matter?

-YD-

The locomotives had a wrench so the crew borrowed unused or duplicate hoses from other units to complete the mu connection. You might get lucky and find a spare hose in the equipment rack in one of the units.

The hoses do not go out of date. They stay in service until they break or get ripped off when uncoupling the units.

Posted from Windows Phone OS 7

Counting the hoses is not required as any part of the daily inspection and/or reporting, nor when taking over a consist. When making up a consist (please, don't use the word "lashup"), however, a brake test is required, at which time it will become evident whether or not there are sufficient hoses.

fbe Wrote:
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> The locomotives had a wrench so the crew borrowed
> unused or duplicate hoses from other units to
> complete the mu connection. You might get lucky
> and find a spare hose in the equipment rack in one
> of the units.
>
> The hoses do not go out of date. They stay in
> service until they break or get ripped off when
> uncoupling the units.
>
> Posted from Windows Phone OS 7

Yes, hoses do go out of date...

When I was a rip track Carman in the mid 70's, I worked the air job. One of the things I had to do was check the date on any car I worked on or tested. I think it was 8 years back then, don't know what it is now. So at least the brake pipe hoses have a date, probably MU hoses too, since the MR hose has to withstand 140 PSI

Good Question, YD...

In my experience, one 'set' of MU air hoses per side is sufficient.
The two 'critical' hoses that must be tight are the 1-1/4" Trainline hose (under the coupler) and the 1" Main Reservoir hose, --closest to the coupler.
Typically the other two hoses (3/4") are kept little more than hand tight, and are easily switched when making up a fresh loco consist.

[Note: the other two hoses are commonly called the "Actuating" hose and the "Brake cylinder-equalizing hose". The brake cylinder equalizing hose sends variable air pressure (from the leading loco) to the brake's application relay valves on all engines in the MU consist --for replicating the same intended cylinder pressures, engine-to-engine. The "Actuating hose" carries a short burst of MR air that goes to a 'brakes release' valve on all the engines. This ensures a quick and fast loco brakes' release function -- it Actuates a quick release!]

The main reason for NOT having a lot of hoses dangling, is the tendency of the non-connected hoses to become subject to sand, dirt & dust contamination while underway.
When, in the future, the dirty hoses get connected-up and the cut-out cocks opened, the dirt will get blown into the engine with the lower hose air pressure.

Yes, there are often 'hose-blanking' pieces (on small chains); but, often mechanics failed to spend the time to match-up the hose-blanks with their intended proper-sized hoses.

Also, in the early [1940s & 50s] MU days, before today's common 'electric sanders', a 4th hose (on each side) was used for air-operated MU'd sanders. The outer hose on each loco was manually activated
according to reverse and/or forward sanders. When, in the 1960s, the AAR Standard 27-pin MU electric cables were adopted, the need for air-MU'd sanders evaporated.

The "27-pin MU cable sanding" specific wire, combined the reverser's position [traction-power contactors on each loco] with the electric signal (manual, or automatic --- wheel-slip issues) that operates the sanders' solenoids. The 'solenoids' are electro-magnet opened, air-flow operating valves that admits high pressure [MR] air to the individual sand traps [to each wheel].

So, the time saving practice of a minimal set of hoses on each loco tended to win-out over the redundancy of so many small hoses on lots of well equipped-locos -- especially a problem on a RR with thousands of diesels -- the need for each loco to be fitted with 4 complete sets of hoses soon became an expensive luxury.

Also, there was a tendency to 'borrow' hoses from foreign thru-power, at hose-short maintenance points. So managements tended to keep only enough hoses on locos to safely operate the brakes.
And, the dirt in the unused-hoses issue is a common bug-a-boo, even in today's environment.

Thanks for the excellent question.

Wes C.

"Yes, hoses do go out of date... "

Well, I never heard of that nor was I instructed go look for any hose dates during a daily inspection. The fines must not be very significant.

If the crew did not hear any hoses leaking during the consist sequence test they were all good to go.

Posted from Windows Phone OS 7

Only need hoses hooked up on one side

Gary Wamhoff
Laramie, WY

Actually you can use a mix of hoses on both sides to complete a set. This can be 4-0, 3-1 or 2-2. The sand hose on the outside is the only one which is direction specific. The right side hose is for forward sand, the left side controls reverse sand. Most second generation units had electric sand control so the sand hoses are superfluous.

Posted from Windows Phone OS 7

josie Wrote:
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> Only need hoses hooked up on one side


Or, you can mix and match. There's only one absolute rule: DO NOT - EVER - NEVER - EVER (is that clear?) crossconnect the IAR and ACT lines between units, even though they have the same size hoses and gladhands. This is a major no-no. The MRE hose has a different gladhand and is therefore impossible to misconnect.

wcamp1472 Wrote:
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>[Note: the other two hoses are commonly called the "Actuating" hose and the "Brake cylinder-equalizing hose". The brake cylinder equalizing hose sends variable air pressure (from >the leading loco) to the brake's application relay valves on all engines in the MU consist --for replicating the same intended cylinder pressures, engine-to-engine. The "Actuating >hose" carries a short burst of MR air that goes to a 'brakes release' valve on all the engines. This ensures a quick and fast loco brakes' release function -- it Actuates a quick >release!]

The "Actuating" line is used to MU the "Bail" signal from the controlling locomotive. Without it, you would bail the controlling locomotive but the independent on rest of the consist would remain set.

Howard

Of course we're talking about the 26 and 30 families of brakes, almost universal today.

The old 6 families in use before 1957, based upon the No. 6 distributing valve (6-ET, 6-DS, 6-BL, 6-EL, K-14, and 14-EL) are compatible with each other but not with the 26 and 30 families. Except, nowever, the 6-BLC is a modification of the 6-BL which is compatible with the 26 and 30 brakes.

The 4th or outside hose was when the sanders were operated by air. Most roads went to using a MU electric wire to run them so they were not needed. The others were for main res, appl & rel, and auct. The glad hands on the MR were different so you could not make a mistake with it.


Nudge

In many of Marty Bernard's and others' photos of Burlington E units, the lead units rarely had MU hoses attached to the capped fittings on the pilots. Was this a typical CB&Q practice?

Craig

When computerized locomotives came out, I often wondered why the independent and bail off functions weren't transmitted through the MU cable, as well as through the MU hoses for quicker reaction through the consist. By sending the signals both ways, the electronic locos would apply and release much faster on a long consist, plus any older units would still respond through their MU hoses.

Should hook up both sides in really cold weather.

Posted from Android

chlacey Wrote:
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> In many of Marty Bernard's and others' photos of
> Burlington E units, the lead units rarely had MU
> hoses attached to the capped fittings on the
> pilots. Was this a typical CB&Q practice?
>
> Craig

Yes, kept them from being damaged.

Some comments:

> Only need hoses hooked up on one side

Tell that to the rocket scientists at Choo Choo U (Amtrak training facility in Wilmington).

>The "Actuating" line is used to MU the "Bail" signal from the controlling locomotive. Without it, you would bail the controlling locomotive but the independent on rest of the consist would remain set.

Bailing has no effect on Independent brake operation whatsoever. It does, however, release an Automatic brake application on all units (assuming the actuating hoses have been properly connected).

>Of course we're talking about the 26 and 30 families of brakes, almost universal today.

>The old 6 families in use before 1957, based upon the No. 6 distributing valve (6-ET, 6-DS, 6-BL, 6-EL, K-14, and 14-EL) are compatible with each other but not with the 26 and 30 families. Except, nowever, the 6-BLC is a modification of the 6-BL which is compatible with the 26 and 30 brakes.

24-RL and 26-L. Although the components are quite different, 24 can be thought of as a non-self lapping 26 system. 26-L can use either a 26 brake valve or a 30-CDW brake valve. It's possible to operate 24 and 26 from 6 and 14, but not the other way around without adding special apparatus. The No 6 system is the longest-lived locomotive brake system: c1895 right through today.

>When computerized locomotives came out, I often wondered why the independent and bail off functions weren't transmitted through the MU cable, as well as through the MU hoses for quicker reaction through the consist. By sending the signals both ways, the electronic locos would apply and release much faster on a long consist, plus any older units would still respond through their MU hoses.

There are two types of computer systems on locomotives: EFI, Electronic Fuel Injection, which is quite common these days, and CCB, Computer Controlled Brake [system] --EAB is the Knorr version and EPIIC is the WABCo one-- which is less common. CCB use computers to operate magnet valves to admit/exhaust air to/from the brake cylinders on the locomotive and brake pipe. The only time the two systems affect each other's operation occurs when the CCB computer opens the PCS. I've not heard of a CCB-equipped locomotive which did not also have EFI, but there are lots of EFI-equipped locomotives which don't have CCB.

You will hear stories from time to time that CCB air sounds are synthesized, but this is an urban legend. The air sounds are the air exiting the various ports in the magnet valves as they are operated by the computer. The MU hoses are functional too because these computerized brake systems must also operate trailing units in the consist, which might or might not have CCB. The engine brakes must also be operable from leading units which don't have CCB, so there is a complete set of pneumatic control equipment in addition to the computer and it's magnet valves. This apparatus also enables the unit to be used --only as a trailing unit (with fully functional pneumatically controlled air brakes)-- should the CCB part of the system fail.

Last I heard, there are no wires in the MU cable which are available for the MU operation of EAB without the air hoses.

EtoinShrdlu Wrote:

>
> Bailing has no effect on Independent brake
> operation whatsoever. It does, however, release an
> Automatic brake application on all units (assuming
> the actuating hoses have been properly
> connected).
>

Sorry but I beg to differ. The purpose of bailing is to release the independent set that was caused by an automatic application. If you released the automatic application, the brake pipe would go back to charged and release the cars. Look in any brake manual, including #6, 8, 14, 24, 24, etc. I don't know how you bail a 30CW but the function is the same.

Howard

sp5623 Wrote:
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> EtoinShrdlu Wrote:
>
> >
> > Bailing has no effect on Independent brake
> > operation whatsoever. It does, however, release
> an
> > Automatic brake application on all units
> (assuming
> > the actuating hoses have been properly
> > connected).
> >
>
> Sorry but I beg to differ. The purpose of bailing
> is to release the independent set that was caused
> by an automatic application. If you released the
> automatic application, the brake pipe would go
> back to charged and release the cars. Look in any
> brake manual, including #6, 8, 14, 24, 24, etc. I
> don't know how you bail a 30CW but the function is
> the same.
>
> Howard


I think he knew that, but just stated it wrong. He has been around long enough to know this fact.

V

SLOCONDR