So what you are telling me is it really has nothing to do with how a steam engine stops/slows down, but the revenue of the railroad?(https://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-surprised.gif)
Some class one track-age uses in cab signals, that the steam locomotive doesn’t have. Also, some class one track-age pings (reads) a transponder in the diesel locomotive for signaling and block detection. Again, something that steam locomotives don’t have. I thought, and its just my thought, without any corroborating information, that the diesel was there, in part, to provide these features, since the steam excursion is running on class 1 track-age along with revenue freight trains, and needs to play nice with the signal system.
But I may be totally wrong in my thinking.
David,
That makes sense to me! (https://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)
Joe Zullo said:
So what you are telling me is it really has nothing to do with how a steam engine stops/slows down, but the revenue of the railroad?(https://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-surprised.gif)
Yep. Steam Engines don’t make money for Class I’s. They just cost them time and money. Heck, it even takes extra on time payments to keep Amtrak on schedule on a Class I. You really think that they would put up with a stopped/broken/ran out of water/ran out of oil steam engine blocking the mainline and costing them even more money? The UP is the only Class I that regularly runs steam, and I think they do as advertising more then anything else.
You are right Craig, for the UP it is pretty much a PR thing. I cannot comment on other steamers, but the UP locos are equipped with cab signals, modern radios and MU stands to control the dismal in tow. As far as braking, it would be better to utilize the dismal’s dynamics on a downhill as you have to keep steam in the cylinders to keep them lubricated. So you are pulling the train down hill, even if it is a little. Couple of my friends are train crew on the UP, they say that if the steamer is within a 100 miles of you then you will be made well aware of it.
There are videos of UP 844 running freight trains without a diesel backup. I don’t know if these routes require the use of retainers or not.
Retainers are valves on the vent pipe of break cylinders and can be set to a 10 or 15 psi setting. They are needed on steep downhill grades to prevent the engineer from ”blowing“ his air by maki the brakes release slower in between sets. The bakes begin to release on a car in a train when the brake pipe is charged back to the normal operating pressure. The cars on the train are not ready to make another brake application until all the brake reservoirs on all the cars are also recharged to to that normal operating pressure. Retainers allow time in between sets for bra reservoirs on each car between brake applications. I don’t believe it would be possible or prudent to make an application at the top of the hill and just “pull” a train down the hill, eventually the the brakes would bleed off and there would be no pressure in the brake reservoirs to make an application, causing a runaway train. Curves on the line cause resistance and will slow the train also and prevent a train making track speed. An engineer anticipates and plans for this additional braking approaching a curves and will release the train brakes going into a curve, reapplying the brakes as the train leaves the curve. This process is known as “short cycling” and without the use of retainers would cause runaways or over speeded trains. When retainers were still used, the trainmen would have to walk the train at the top of the hill and manually set them in the desired position for the appropriate amount of cars. At the bottom of the hill, the trainmen would have to reverse the process.
On steam locomotives, there is a valve in the cab to cut out the driver brakes. This is to prevent the drivers from sliding in the case of an emergency brake application. The tender brakes will still operate but generally as soon as an engineer is finished making an automatic brake application on the train, they would release the independent brakes to keep the train stretched out.
I worked as an engineer on the Durango & Silverton for 2 seasons. The D&S uses a straight air brake system in addition to the automatic brake system. This essential consists of a second brake pipe running the length of the train that is plumbed directly into the brake cylinders. It allows an engineer there to add and remove air into the brake cylinders at will. The brake reservoirs remain fully charged in case of the need for an emergency brake application. I believe this was added in the 80’s to prevent flat spots on car wheels and potentially provide a smoother ride.
They used to do that more often. Pulling freight cars during a light engine move was an easy way to increase the number of brakes in the train. Again, it was done for the purpose of braking and saving the loco’s brakes. You can find a lot of older videos of those locos were they are pulling a coupe dozen freight cars.
Patrick Kramer said:
There are videos of UP 844 running freight trains without a diesel backup. I don’t know if these routes require the use of retainers or not.
Great discussion, I learned a lot. Thank, guys.