Steam & Excursion > Steam & PTC, Part 2

Power Knock-down Switch, P.C. switch, etc....

When diesels first appeared, they used a pressure sensor in the trainline brake system.
When the train experienced an Emergency Brake Application, this switch set the engine governor to 'idle' RPM speed, and shut OFF the Main generator' s excitation field. Thus killing all power to the train.

In this state, thee engineer can only fully release the loco's brakes ( all locos, if M.U.d). While the train rolled to a stop, eventually.

On passenger trains, it was soon discovered that train separations could occur while traveling at high speeds....
In such a case, the two sections rolled to a stop, with the brakes applied. 
Depending on where the break-in-two occurred, a heavier section took longer to stop than a lighter train segment.
Setting the stage for a 'run in'...... where the operation of the train with the power attached, momentarily advances away from the heavier section, eventually stopping a short distance away --- only to be rammed by the still decelerating heavier train segment.
The classic run-in situation...

This resulted in many injuries and deaths because the engineer had no way to accelerate AWAY from the still rolling segment.
The P.C. switch killed all his power, which if available, is capable of dragging the attached cars well ahead of the heavier segment....
thus avoiding the disastrous RUN-INS.

Steamers ALAWS had the capability of powering-away, in these situations, simply by going to full power capacity, at any time.
At some point Amtrak locos had the P.C.eliminated or disabled, thus giving engineers the  ability to apply 'full diesel power',
at any time and especially in break-in-twos.

Adding "power knock down" features to steamers is ridiculous, unsafe and unnecessary.
Amtrak doesn't use it, we don't need it.

We all need to fight any such modifications with all the fight we have, engineering, lobbying and safety related.
APPLY NO POWER RECUCTIION FEATURES ON STEAM LOCOS, AT ANY TIME.

​W..

I like your logic Wes.

For mailine steam excursions, host railroads issue bulletins exempting individual lococmotives and/or trains from mandatory inspection procedures when trackside detectors mistake the firebox for a hot axle. I would think a similar bulletin could be issued allowing the train to run without PTC. Mainline steam excurions typically have an aubundance of alert personnel in the cab, and quite a number of officials and inspectors onboard, that serve to keep the crew on thier toes.

MP733 Wrote:
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> For mailine steam excursions, host railroads issue
> bulletins exempting individual lococmotives and/or
> trains from mandatory inspection procedures when
> trackside detectors mistake the firebox for a hot
> axle. I would think a similar bulletin could be
> issued allowing the train to run without PTC.
> Mainline steam excurions typically have an
> aubundance of alert personnel in the cab, and
> quite a number of officials and inspectors
> onboard, that serve to keep the crew on thier
> toes.

You mean, like a certain 4-8-4 on the UP, which nearly got by a stop signal even with all of the above onboard?

Therein lies the crux of the debate.  PTC is intended to be a fail safe to backup the inevitability of human error, but where is the dividing line between fail safe and the opening of an unintended can of worms.

Mary McPherson
Dongola, IL
Diverging Clear Productions

bioyans Wrote:
-------------------------------------------------------
> MP733 Wrote:
> --------------------------------------------------
> -----
> > For mailine steam excursions, host railroads
> issue
> > bulletins exempting individual lococmotives
> and/or
> > trains from mandatory inspection procedures
> when
> > trackside detectors mistake the firebox for a
> hot
> > axle. I would think a similar bulletin could be
> > issued allowing the train to run without PTC.
> > Mainline steam excurions typically have an
> > aubundance of alert personnel in the cab, and
> > quite a number of officials and inspectors
> > onboard, that serve to keep the crew on thier
> > toes.
>
> You mean, like a certain 4-8-4 on the UP, which
> nearly got by a stop signal even with all of the
> above onboard?

I was told by someone that claimed to be in the meeting (yea, I know) that at a committee meeting with the FRA the question of exempting historical equipment from PTC requirements was discussed.  The class 1's decided to defer to Union Pacific, since they had the biggest historical fleet.  Union Pacific said they didn't need an exemption, so that idea died.

I doubt that there would be an avenue for a class 1 to issue what you are talking about in PTC territory.

MP733 Wrote:
-------------------------------------------------------
> For mailine steam excursions, host railroads issue
> bulletins exempting individual lococmotives and/or
> trains from mandatory inspection procedures when
> trackside detectors mistake the firebox for a hot
> axle. I would think a similar bulletin could be
> issued allowing the train to run without PTC.

The problem here is that no sound business strategy or planning can be conducted on the likelihood of getting a waiver. There are already too many logistics, variables and challenges. The only sound approach is to make your locomotive compliant.

When a railroad invests millions upon millions into a technology, asking for a waiver is like filpping a coin and the very few steam operators out there can't rely on those odds.




 

The average operator is already staring at huge insurance premiums. I can't imagine those same insurance providers looking favorably on an organization not implementing the "silver bullet" that is to keep all trains completely safe forever and always. We may see that the emperor isn't wearing clothes, but ultimately that won't matter.

Also, once a railroad invests in all that tech and infrastructure, they'll have their own lawyers in their ears as well. I can't ever see a waiver for a non-PTC equipped steamer unless it's towed by a PTC-equipped locomotive.

Going PTC, with all its unknowns, expense, and problems, certainly doesn't guarantee getting any rail time, but it's the only responsible option.




nathansixchime Wrote:
-------------------------------------------------------
> MP733 Wrote:
> --------------------------------------------------
> -----
> > For mailine steam excursions, host railroads
> issue
> > bulletins exempting individual lococmotives
> and/or
> > trains from mandatory inspection procedures
> when
> > trackside detectors mistake the firebox for a
> hot
> > axle. I would think a similar bulletin could be
> > issued allowing the train to run without PTC.
>
> The problem here is that no sound business
> strategy or planning can be conducted on the
> likelihood of getting a waiver. There are already
> too many logistics, variables and challenges. The
> only sound approach is to make your locomotive
> compliant.
>
> When a railroad invests millions upon millions
> into a technology, asking for a waiver is like
> filpping a coin and the very few steam operators
> out there can't rely on those odds.
>
>
>
>
>  

Posted from iPhone

Jared Hamilton
Scott Depot, WV

Having your mainline capable steam locomotive fully compliant and equipped with PTC will only enhance your chances of getting out on a mainline once the mandate has been met.

The ability for PTC to close the throttle during a penalty or emergency brake application is vital for a number of reasons that are too complicated to list here.

As previously mentioned, requesting an FRA waiver is time consuming and uncertain as the request may be denied. If a waiver is granted, I doubt that it will allow mainline speeds to be attained and would likely restrict the movement to 30 mph.

There are a multitude of other factors involved once PTC has been installed, but getting the equipment on the engine is the first step.

With a reasonable amount of experience in the matter, I will once again say that having a fully compliant PTC system on your locomotive will greatly enhance the possibility of a railroad authorizing a special movement and may even increase the chances of such.

R.R. Conway

Don't worry about closing the throttle in a PTC penalty application.

The better answer is to automatically center the valve gear by a simply addition to the power reverse gear it seems to me. 

I've done some design work on my own toward that end, and particularlty with an Alco power reverse it is relatively simple from a forward direction of movement.



Edited 1 time(s). Last edit at 03/17/17 11:36 by Walschaert.

Walschaert Wrote:
-------------------------------------------------------
> Don't worry about closing the throttle in a PTC
> penalty application.
>
> The better answer is to automatically center the
> valve gear by a simply addition to the power
> reverse gear it seems to me. 
>
> I've done some design work on my own toward that
> end, and particularlty with an Alco power reverse
> it is relatively simple from a forward direction.
>
>
> SWR

Centering the power reverse with a reasonably well open throttle will not do much to slow down. The lap & lead will STILL be providing steam to the cylinders. The proper way to "reduce power" is to close down the throttle so that ONLY the pilot valve is remaining open. Besides, what would happen if the "power reverse centering" mechanism failed during operation?

HotWater Wrote:
-------------------------------------------------------

> Centering the power reverse with a reasonably well
> open throttle will not do much to slow down. The
> lap & lead will STILL be providing steam to the
> cylinders. The proper way to "reduce power" is to
> close down the throttle so that ONLY the pilot
> valve is remaining open. Besides, what would
> happen if the "power reverse centering" mechanism
> failed during operation?

Centering the reverser together with a penalty application, particularly at an emergency application rate would be sufficient to bring the train to a stop in case of an incapacitate crew as is the ultimate purpose for PTC enforced stops.

If it failed enroute - it would be handled in the same manner as an enroute failure of any other part of the PTC apparatus.


SWR

Walschaert Wrote:
-------------------------------------------------------
> HotWater Wrote:
> --------------------------------------------------
> -----
>
> > Centering the power reverse with a reasonably
> well
> > open throttle will not do much to slow down.
> The
> > lap & lead will STILL be providing steam to the
> > cylinders. The proper way to "reduce power" is
> to
> > close down the throttle so that ONLY the pilot
> > valve is remaining open. Besides, what would
> > happen if the "power reverse centering"
> mechanism
> > failed during operation?
>
> Centering the reverser together with a penalty
> application, particularly at an emergency
> application rate would be sufficient to bring the
> train to a stop in case of an incapacitate crew as
> is the ultimate purpose for PTC enforced stops.

An "incapacitated crew" on a diesel or electric locomotive is one thing, but such an occurrence in todays modern main line steam operations is HIGHLY unlikely, thus simply closing the throttle down to a drift is would be far more practicable and doable.

> If it failed enroute - it would be handled in the
> same manner as an enroute failure of any other
> part of the PTC apparatus.

I meant, what happens if the "centering device" fails and the Engineer can no longer move the power reverse gear?


> SWR

HotWater Wrote:
-------------------------------------------------------

>
> An "incapacitated crew" on a diesel or electric
> locomotive is one thing, but such an occurrence in
> todays modern main line steam operations is HIGHLY
> unlikely, thus simply closing the throttle down to
> a drift is would be far more practicable and
> doable.

While either would be acceptable, It's seems to me easier and more practical to handle this on the power reverse side.  At the end of the day, as long as it could be demonstrated to perform the desired function, it would work. 

As to speculation about liklehood of incapacitated crew - that's a bit of a red herring.  They system must be capable of stopping the train without human intervention.





>
> > If it failed enroute - it would be handled in
> the
> > same manner as an enroute failure of any other
> > part of the PTC apparatus.
>
> I meant, what happens if the "centering device"
> fails and the Engineer can no longer move the
> power reverse gear?
>


Stop the train, and remove the pin from the linkage. 

What would happen if the throttle failed?  Stop the train and remove the apparatus.



 

Walschaert,

I don't know how much main line "big steam" experience you have, but you certainly have all the answers.

About 9 years overall between helping restore and then operate a 4-8-4 on a Class 1.

About 31 years on the railroad almost all in the Operating Dept.


 

Walschaert Wrote:
-------------------------------------------------------
> About 9 years overall between helping restore and
> then operate a 4-8-4 on a Class 1.

OK, so which 4-8-4 and where does it operate?

> About 31 years on the railroad almost all in the
> Operating Dept.