Safety cab

[Anonymous]

What exactly is a safety cab? Is it one with lots of reinforcing steel for crash protection? Think the FRA designates the crash worthyness of all passenger cars and engines. If this is the case every engine and car would qualify as a safety cab.

[Anonymous]

Most if not all of the new wide cabs are safety cabs. I'm sure it has to do with their cra***est standards, but also if I'm not mistaken it involves the sound insulation as well as crew comfort. With the idea being not to have the whistle and track noise drive you nuts over 10 hours in the cab and thus help with crew fatigue.

I'll confess to not be an expert, but that's what I''ve read.

MV

cda.mrs.umn.edu/~vandenbm

[vsmith]

"...All cab designs meet FRA standards for crushing, shearing from the frame, and penetration. Collision posts at the front of the nose resist shearing and crushing forces applied in the direction of motion...."





How do they test that? Any video?

[Overmod]

Isn't there some additional safety in the isolated-cab variants, because high shear forces can pop the cab loose as a unit rather than deform its structure against the high momentum of the rest of the locomotive and train?

Don't know whether the 'encapsulated-deck' idea of the F-111, XB-70 and Space Shuttle might be useful for some of the crash scenarii that involve safety cabs. I do know that I started thinking along those lines after seeing an article in Trains -- which you can probably reference exactly -- which described an Illinois Central collision with a gas truck (the locomotive was an E unit, I think an E9). The collision did very little damage to the sheet metal, but flaming fuel entered around the crack of the nose door and through the numberboards and killed the engine crew before the train slowed enough for them to exit. Ever since then, my 'locomotive designs' have had pressure-sealing windows, doors with compression sealing, and methods to displace a stiffened 'crew compartment' upward if exposed to more force than the locomotive structure can withstand. (Naturally you can't get this to work very well without full air conditioning (or perhaps better stated, 'air tempering' with separate ventilation exchange to the outside, which would be cut off in the event of collision,etc.), which wasn't cost-effective back then and in many places isn't considered so now...)

[jeaton]

A little beside the point but I recall that incident. The accident not only took the life of the engineer and fireman, but also a young man that Alan Boyd had just recently hired as Assistant to the President and the trainmaster on board for the orientation. Another co-worker that I knew fairly well was also scheduled to make the trip, but had to cancel at the last minute.

I recall that the nose access panel on the E unit had appearantly not been replaced after some servicing, and that allowed some much flaming fuel into the cab that there was no chance for survival.

Jay

[edblysard]

I can tell you from personal experience, the nose doors on both the GE and EMDs are heavy, thick, and designed with a inner lip, formed from the body steel, that protrudes out from the body at 90 degrees, with a thick flexible gasket around it's outter rim, over which the door closes, forming a semi air tight seal.
Imagine the doors on a Naval vessel, including the door dog, or handle/latch that snugs the door down.
Very heavy, thick and solid...

From the above discussion, I would agree that part of the reason for such a door is to prevent any substance from entering the compartment, and to reduce wind noise and draft.
The inner door to the stairwell is injected and formed plastic, with a standard latch.

Ed

[broncoman]

Was the BQ23-7 cab deemed unsafe by the FRA or was it something that CSX determined was a problem. I thought I read in a previous post that one unit had been involved in a road crossing incident and things stemmed from that.

Dave

[Overmod]

I've looked to see if I can find an actual accident report, but no luck. Certainly having the cab right up on the front beam, with no hood or nose in front, wouldn't make for particularly high crashworthiness -- wouldn't be surprised to find only a single door, too... albeit it appears to be the kind of armored and gasketed door Ed describes. One very great problem I can see is that this door would either have to be open or very carefully worked in order for crews to pass safely from the cab to the front gangway -- I can just see someone swinging this door open and bashing somebody outside a good lick! (No window in the door only makes it worse!)

This cab appears to be similar to the construction used on some of the GE electrics of about this period, particularly the Mexican ones.

BN had some GP50s with 'supercabs', but these locomotives had a conventional short hood. Any opinions on this list about those?

[corwinda]

QUOTE: Originally posted by Overmod

Mark, isn't there some additional safety in the isolated-cab variants, because high shear forces can pop the cab loose as a unit rather than deform its structure against the high momentum of the rest of the locomotive and train?

Don't know whether the 'encapsulated-deck' idea of the F-111, XB-70 and Space Shuttle might be useful for some of the crash scenarii that involve safety cabs.

I'm not sure that there would be any advantage to the cab detaching if the occupants aren't restrained - ie seat belts. Think being tumbled about inside a giant steel ball.

[broncoman]

I would think they could devise a ejection cab like the commanche helicopters have. It would just have to be mandatory to be belted in while in the cab. I am surprised that crew are able to survive just being thrown around in the cab on impact....something about an unstoppable force and an imovable object.

[Anonymous]

QUOTE: Originally posted by broncoman

I would think they could devise a ejection cab like the commanche helicopters have. It would just have to be mandatory to be belted in while in the cab. I am surprised that crew are able to survive just being thrown around in the cab on impact....something about an unstoppable force and an imovable object.

Then the problem becomes where are you going to eject them to? They have to come down somewhere, and especially in the case of trains it is very hard to tell what the safest direction to go is. In most cases it is probably better to crash-proof the cab a little more and ride it out. Same idea as in modern autos.

[AntonioFP45]

It's pretty neat that EMD is reverting back to the AAR style controls. I've read in the past that engineers hated what they called: Trolley Car Control Desk!" where knees are knocked.

I've had the privilege of sitting in engineer's seats in 1st and 2nd generation locomotives back in the 80s when I was in the National Railroad Historical Society. It seemed like the controls were positioned comfortably for the engineer regardless of his or her height.

[Overmod]

The point of the detachable, reinforced cab is the same as for this kind of cab on over-the-road trucks.

In both cases, impact with what the train hits is the least of your worries. Behind you is a long. loaded mass, attached by the flimsiest of connections relative to its substantial momentum and inertia, which is going to keep moving even if your cab stops short.

On locomotives running short-hood-forward, there's a heavy engine behind the cab, and any impact that pushes the cab backward without detaching it is likely to crush even the heaviest framing against the engine block. This is why hitting a dropped bridge counterweight is usually an unsurvivable accident -- the chassis runs under, the cab stops short ... the superstructure of two or three units winds up being about 20 feet long.

I still think sometimes about Jerome Evans and whether he might have lived if the AEM-7s had been given 'survivable' cabs (which to me, for that wreck, would imply both detachability and high-voltage electrical isolation).

[Anonymous]

Does anyone have any safety history on the cab-ahead designs that SP used in the steam era? I don't think that I would want to be crushed backwards into the boiler. Besides that, did the manufacturer (were they built in SP shops, or by somone like Baldwin?) provide any sort of crash protection into these locomotives?

[edblysard]

Overmod,
All of the wide or safety cabs have a over-ride style front pilot, anything they hit, other than another train, is pushed down and under the nose, those equipped with a plow will trap most autos and truck bodies between the plow and the front walkway/overide lip.
The crash post are located just inside the outer door, (a side note, the post have lift holes in the top of them, you can remove the nose portion and pick the entire locomotive up with them) along with the event recorders and the toilet compartment.

Most of the wide cabs have a door stop for the front door, either welded to the walkway, or built into the hinge, that prevents them from being opened all the way back, flat against the nose.
As for the door itself being a hazzard, with one man crews, (engineer and conductor) its not a problem, and even with two and three man crews, it is rare that more than one person at a time is out on the front porch at the same time with the locomotive moving.

From a crewmans point of view, even though I perfer a SD40-2 (the locomotive version of the Chevy 1/2 ton pick-up) if I was to be involved in another accident, I would want the wide cabs protection over the older locomotive's.

As for rearward protection, if you manage to run into something massive enough, and at a speed fast enough to break the prime mover lose from its cradle and cause it to enter the cab, then its a moot point as to what crushes you, the prime mover or the other locomotive and train you run into.

Ed

[zardoz]

One become quite aware of the flimsiness and lack of protection a suburban cab-car provides when your train is doing 70mph and you see a semi trailer stretched across the tracks in from of you.

[oltmannd]

QUOTE: Originally posted by Overmod

Mark, isn't there some additional safety in the isolated-cab variants, because high shear forces can pop the cab loose as a unit rather than deform its structure against the high momentum of the rest of the locomotive and train?

Don't know whether the 'encapsulated-deck' idea of the F-111, XB-70 and Space Shuttle might be useful for some of the crash scenarii that involve safety cabs. I do know that I started thinking along those lines after seeing an article in Trains -- which you can probably reference exactly -- which described an Illinois Central collision with a gas truck (the locomotive was an E unit, I think an E9). The collision did very little damage to the sheet metal, but flaming fuel entered around the crack of the nose door and through the numberboards and killed the engine crew before the train slowed enough for them to exit. Ever since then, my 'locomotive designs' have had pressure-sealing windows, doors with compression sealing, and methods to displace a stiffened 'crew compartment' upward if exposed to more force than the locomotive structure can withstand. (Naturally you can't get this to work very well without full air conditioning (or perhaps better stated, 'air tempering' with separate ventilation exchange to the outside, which would be cut off in the event of collision,etc.), which wasn't cost-effective back then and in many places isn't considered so now...)

I don't think this was even considered. If it was, it was never conveyed to the customer. I was the "keeper of the specs" at Conrail when we got the first isolated cabs. Sole justification was reduction in noise. Reduction in vibration was secondary consideration. Crashworthiness was never discussed.

The "wide" cabs took care of several problems at once. One was improved toilet facilities which were better for the train crew and easier to maintian as well. Another was a better place to mount train control equipment. A third was better HVAC.

[ShaunCN]

the first "wide cabs" or safety cabs where developed by CN. They had a 4 window cab and a door on the nose. These cabs where built on GP40-2's, GP38-2, Dash8's SD40-2s. even some dash9's. Now we have "the safety cab" made by EMD and GE wich is a rip off of the original CN verision. Check out my pic below for a CN SD40-2W with the safety cab.

[M636C]

Overmod still exists - or someone knows his password!

Not having seen this thread before, I might as well add some comment on the Clyde/EDI isolated cabs which are more capsule like than most, on the AN and Q classes at least. The cabs sit in a cradle like structure that surrounds the cab up to waist height, with an entry from the rear and collision protection in front. So far none have been intentionally ejected from the locomotive to my knowlege.

Peter