Helper Engines

[mononlaf]

How to use helper (pusher) engines?

In another thread, http://forums.auran.com/trainz/showthread.php?t=10683 , on AI Engineering, we have discussed adding a subconsist to the rear of a train. Basically, we figured out that either you have to uncouple and send the road engine off scene, or you have to move the road engine's driver and exchange messages with the switch engine's driver, using the postmessage and waitformessageandclear commands. Furthermore, even though there is no driver in the road engine, uncouplez and uncouplez from work with respect to the road engine, not the switcher.

When experimenting with no driver in the road engine and using couple-at-trackmark to add a few cars to the rear of a train, I had the switcher move the whole train back and forth. When this happened, the switcher controlled the power of both engines - both revved up or down at the same time.

It occurred to me that, added cars or not, this was how to couple up a helper engine to help a heavy consist up a steep grade.

The posts in the other thread cover several hoops that you have to jump through to add another engine, at least in the ways that we were going about it.

Does anyone know of rules or methods for adding and releasing helper engines to trains? One thing seems certain - a single train can have only one driver and one set of driver commands and rules. The command, uncouplez from, works only with respect to the lead engine, and if there are more than 20 cars between lead engine and helper we are in trouble unless we stop and break the train when we want to release the helper.

Advice, knowledge, or work-arounds anybody?

Dick

P.S. - Some of us are using 2004, others 2006 - the techniques don't seem to differ between them.

 

[stagecoach]

Dick trainz always places the driver in the front running engine, so if the switcher was the rear of the direction then the road engine is the front and the uncouplez would uncouple the road engine. try a change direction before the uncouplez. The only other alternative i know is the "uncouplez from" command, but you need to know how many wagons back the switcher is.

 

[mononlaf]

Stagecoach -- you are a genius! Change Train Direction worked like a charm. Thanks not only for the suggestion but the explanation of what is going on.

For others that are interested:

An AI road engine pulled a consist in and stopped. The driver (Dave) moved to another engine sitting on a nearby siding and sent a message to the timetable with a postmessage command (on the DLS). An AI driver (Kenny) in another engine on a siding behind the consist picked up the message with a waitformessageandclear command (also on the DLS). Kenny then moved up, applied "couple at trackmark" to the rear of the stopped train, which still had a now unoccupied engine on the front end. Kenny ran the whole consist forward (controlling the power applied by both engines) to a designated trackmark and stopped. He followed change train direction and uncouplez commands, sent a message, and proceeded to the rear to another trackmark. As soon as Dave picked up on Kenny's message, he moved back to his original engine and continued on his way according to his list of commands. He did not need another change direction command. The uncoupling and switching from one driver's control to another was almost instantaneous.

Thanks again to stagecoach -- what made this move so smoothly were the postmessage and waitformessageandclear commands. A note on the latter - if you use CMP to search, you will find two versions for each, two of them being designated for TRS 2006. However, the 2006 waitfor... command has a script error. I found that the waitfor... version for 2004 works fine in 2006.

The author of the message commands very kindly provided me with a fix fot the script error, but since 2004 works fine, there is no point in repeating it here.

Dick