The recent post about the 557 got me thinking, what exactly is going to happen to mainline steam when PTC comes around? In no way do I believe it will be the end, because UP just spent a bunch of money on 844, and are working on the 4014, but how exactly will those said locomotives operated in a PTC environment?

I can't really think of a way to install PTC on a steam locomotive, will the FRA issues waivers for operators? Or is this another one of those huge unknowns.

It is possible to install PTC on a steam locomotive, just requires cubic $$$$$ and some ingenuity.

PC

Tails brings up a good question... As I see it there's three questions to answer (and this forum might be a good place to solve some of those questions);
1) What equipment is necessary?
2) What is the power requirements for the equipment?
3) Where can the equipment be installed?

There are multiple suppliers of PTC equipment, and the form and design of the components varies from builder to builder. On most systems the main components are the processor unit, a power supply that may be separate or built-in, a memory module, and an operators interface. Additional hardware required includes a variety of sensors, magnet valves, speed pickups, and antennas, and the antenna mounting platform. For a steam locomotive, equipment for control of the throttle and/or power reverse is an additional factor.

The "form" of most of the modular components fits the microprocessor shelf in a modern diesel locomotive.

On a steam locomotive, available space and component placement are the challenge. The processor and memory need a protective enclosure, there has to be some space to mount the operator interface (probably above the engineer), and there needs to be a battery box (64v battery, 74v charging) and provision for charging the batteries. Another problem appearance-wise is the antenna array and its platform, it is obvious and ugly.

The description I provided is roughly based on the Wabtec system as applied to CSX SD40-3 locomotives. It does not apply to Northeast Corridor PTC/ACSES/ATC combined systems which require a great deal more space in the locomotive.

PC

I know that 614, years ago, was equipped with cab signal to operate over NJ Transit's lines. With a diesel or electric, 'power knockdown' wouldn't be a problem, and air brakes are air brakes. I had often wondered, though, about closing the throttle on a steam locomotive with either cab signal or now PTC.

Would some sort of 'slip linkage' (for lack of a better term) with an air cylinder do the trick? With the air cylinder in one position, the throttle functions normally, the linkage is rigid; when told to close the throttle, the cylinder works through the slip linkage and shuts off steam. (Tough to describe, I know-)

DC power could come from an inverter off the 32V headlight generator, or another separate dedicated generator. On the Tornado, the Brits fitted an alternator to one of the tender axles, which charges batteries. LED headlights as well...

Could the antenna array be placed on top of the water space in the tender, with some sort of 'toolbox' built around it as camouflage?

Interesting thread, lots of challenges ahead, if steam is to operate on lines where PTC is required.

I'd hide it UNDER the coal :-)

Seriously, many of the mainline locomotives operate with a canteen these days, and it seems to me that since the canteen has no "prototype", to borrow the modeler's term, all the housekeeping functions, antenna, batteries, charging generator can be banished to the canteen where they should not be objectionable. If that means the canteen needs to be permanently drawbarred to the tender to make it part of the "locomotive", so be it. The problem doesn't look insurmountable to me.

That throttle issue brings up an idea... Just thinking off the top of my head here, but if you have a throttle with a clutch or some sort of lock on it to prevent movement you need a mechanism that can both unlock the throttle and close it. I'd have to sketch it out, but couldn't an air or hydraulically driven piston be used to both unlock the thottle an close it in one motion?

Dylan, that was exactly what I was suggesting.

While there is a radio antenna that is mounted on top for the purposes of receiving data (receiving temporary speed restrictions), the antenna that Mr. Cook is most likely referring to is the large ACSES receiver antenna that hangs underneath the vehicle. This antenna is used for reading the transponders which are permanently mounted in the gauge of the track, which provides data to the onboard equipment so that the system knows where the train is physically located on the railroad and at what speed limit that train should be operating.

In the picture below, you can see the cab signal track receiver coils which are directly behind the pilot plate. The large silver box hanging from the bracket is the ACSES antenna which reads the transponders. On this particular locomotive, the ACSES antenna is mounted under the F-end nose, however these antennas can be mounted almost anywhere on the underside of the equipment, they do not have to be on the leading end of the equipment in the same manner as the track receiver coils.

PTC requires a non-overrideable throttle shut-off and non-overrideable braking capability - not exactly possible with steam.
I'm really astonished that the PTC law - which was poorly written and rushed through - hasn't been repealed yet. Instituting a Canadian-style system would cost substantially less and give comparable levels of safety.

CD

So if that's the case, what happens when the law goes into full effect? No more mainline steam?

26L and cab signals have been successfully adapted on many steam locomotives which shouldn't have too much issue complying with the braking requirements. A fancy mag valve could be adapted to control a steam shut off
on the dry pipe or delivery pipes. It takes some engineering but none of the above is impossible with a steam locomotive.

What happens when you suddenly and involuntarily chop the throttle and loose the draft?
What happens when your now worried crew runs up to a hot fire and low water?
(Presuming that the cab crew is somehow incapacitated and that's why the PTC triggered)
Will the drivers lock up when the brakes get applied?
I suppose having the drivers flat or even have the boiler explode due to low water is 'better' then a wreck or derailment in a loaded passenger train. But still some things to consider.

I would hope a sudden stop with the throttle closed wouldn't result in a boiler explosion. I expect a qualified fireman to be carrying water high enough that a quick stop wouldn't result in a low water situation that would jeopardize safety. As for the draft aspect I assume you hopefully have a functioning blower if you need it. I have been a part of at least one unexpected quick stop while firing a steamer and I simply made sure my injector was on and functioning properly. At no point did I feel like I needed to jump off and run for the hills. I can see possible flat spots if you can't bail or damage to cylinders due to lack of steam for lubrication and cushion. But PTC isn't meant to save equipment as much as human lives. Now keep in mind I don't nessicarily agree with the PTC mandate fully however I disagree that it cannot be adopted to steam locomotives.

Additionally what happens if all the crew members in the cab of s steamer become incapacitated now? Is PTC safer? Of course it depends on the situation but the safest train is usually the one that never moves and PTC should at the very worst keep the train static.

Low water is not a factor of not running, not since the crosshead pumps were replaced by injectors back in the 1870s. It's caused by faulty gauge glasses, bad firing or bad water and bad firing. Loss of draft simply makes the fire want to burn less. I've been firing when the air was pulled - it was slightly uncomfortable, but nothing likely to create a panic situation. I turned the gun on for cooling rather than water level to keep the pops from opening and creating another distraction noise to contend with. I also cracked the blower, not to make steam but to clear smoke and keep the fire alive.