Western Railroad Discussion > Operational Question

When an engineer has a train so long that he cant see the rear, and he goes over a diverging switch movement that requires a speed reduction only as long as his train is over that switch, then he can proceed back to full speed, how does he know/calculate when he can resume his speed? 



Edited 1 time(s). Last edit at 04/26/24 14:20 by Amtrak-P42.

Use the distance counter? Train length should be programmed in on display screen right?

Posted from Android

Yes, the distance counter, with the train's length programmed in, is what has been traditionally used for that.  However, now PTC will "tell" you when you're over it because the Max Speed will change to the higher speed.

Still, the distance counter is a useful tool to let you know when you clear a crossing, control point, a detector that talks to you, etc.   

The engineers need to remember to use their turn signals when going through a diverging signal.  The road formen have been going after engineers for not using them.

You can also use time. Lets say you have a 10 mph slow order and train thats 5280ft long. That takes 6 mintues to clear. 20 Mph slow order and same train is 3 min.  Ive told conductors in the past well its gonna be x minutes before we clear that. So they checked there watch, then checked when the foot coutner went off HOW DID YOU DO THAT. 

You can also count the line poles...er, wait, scratch that one.

skinem Wrote:
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> You can also count the line poles...er, wait,
> scratch that one.

Yep....mostly sawdust now!

NSDTK Wrote:
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> You can also use time. Lets say you have a 10 mph
> slow order and train thats 5280ft long. That takes
> 6 mintues to clear. 20 Mph slow order and same
> train is 3 min.  Ive told conductors in the past
> well its gonna be x minutes before we clear that.
> So they checked there watch, then checked when the
> foot coutner went off HOW DID YOU DO THAT. 


Whoa whoa whoa whoa.....math? What is this sorcery you speak of.

Posted from Android

Traditional math or the new math invented in the Seventies?
 No problem get out your "sliderule" and calculate it. "Sliderule"? We don't need no stinking sliderule. I'm old enough to remember when HP introduced its groundbreaking calculator. For a mere $400 (close to 4 weeks of my pay then) or so you had a precision electronic battery powered calculator that was like a miracle, excepting it required the input to be done in what was known as "Reverse Polish Notation", a very unintuitive method of entering the data to be calculated. It did not follow the text book equations most people were accustomed to. Not too much later Texas Instruments introduced their first calculator, a little hazy in my memory now, maybe the SR11 (as in Slide Rule 11)? It was much less expensive and accepted the more familiar direct formula based entries. My wife presented me one as a Christmas present as I was doing Trigonometry at work using pencil and paper, calculating gear centers using self taught Trig from "Machinery's Handbook". I was a mess in High School and to say math was not my strong suite is an understatement! That calculator was a God send! Today, what's a calculator? My alleged smart phone is actually smarter even if the spell correction feature is awful!
 Never mind just count the now saw dust piles along the ROW!
OMG, How did we survive?
gonut

An odometer no different than that of your car, except calibrated in feet vs miles and fractions thereof. 

I do wonder if they add in a buffer for incorrect car data or maximum slack. For example say they list the train at 5,940 feet in the computer, does the engineer wait until 6,100 feet on the distance counter just to be safe? 

I use the counter, but sometimes it's off, especially on the older head end boxes. So I made up a chart that converts train footage to tenths of a mile. For example, 10560 ft is 2 miles. If my train is 10400 ft I just go to the next higher mile/tenth of a mile (2 miles in this case) and add or subtract the distance to the mile post location. We still have miles and quarter posts.

The PTC display only shows about the first 7200 feet of a train. Anything longer and you have to use something else. The PTC does display maximum speed allowed for the train's location, so the allowable speed would change when the rear of the train clears a speed restriction.

Posted from Android

Previous to the computer nonsense, the engineer would check the speedo and counter at known accurate mile posts. Then you knew the counter and speedo were accurate when operating over the road.  With the computer system on the motors, the counter is accurate.  So I've been instructed.  With the advent of PTC, the train information is plugged into the computer by the engineer and away you go.  By the way, the engineer if responsible for the accuracy of the information in the computer.  PTC will let you know when you can increase speed.  Unless you have cars in the train that you don't know about.  I was yarding a train at Montclair (CA) with the conductor on the ground, when he calls and says"hey, we've got bays back here".  Not supposed to have any bays.  We had an extra 1200ft of train that was not reflected on the paperwork.  Surprise, Surprise, Surprise!!  This ment that I was speeding out sidings faster than I was supposed to because my information was not accurate.  Not a rare occurance.

okcrr Wrote:
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> An odometer no different than that of your car,
> except calibrated in feet vs miles and fractions
> thereof. 
>
> I do wonder if they add in a buffer for incorrect
> car data or maximum slack. For example say they
> list the train at 5,940 feet in the computer, does
> the engineer wait until 6,100 feet on the distance
> counter just to be safe? 

You just use what the paperwork gives you. It's pretty accurate and seems to account for potential slack. If you're using a counter in count down from preset mode and you know it's off, it is somewhat common to use the correct "adjusted" footage. If you're fitting into a siding or spot that you barely fit into you want to use your actual length (or correct length corrected for a slightly off counter). It's less common with PTC these days but still doesn occasionally happen.. A hundred or even couple hundred foot isn't likely to be a concern in terms of train handling for speed restrictions. On a 3 mile long train it's commonly going to be off by more than that.

sidewinder Wrote:
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> Previous to the computer nonsense, the engineer
> would check the speedo and counter at known
> accurate mile posts. Then you knew the counter and
> speedo were accurate when operating over the
> road.  With the computer system on the motors,
> the counter is accurate.  So I've been
> instructed.  

From what I understand PTC just uses the 2nd axle instead of the 1st axle. The lead axle wears faster so it's generally more accurate. I've seen a couple of trains that PTC speed was responding like a speedo would when it is "having issues", cable binding or something like that. As I was slowing down to stop at a signal it was repeatedly giving me innacurate (much faster than actual and the display speedo) speeds. Made for an interesting time trying to get it up close to the signal to get relieved at.