What are the factors involed when you slip going up a grade?

[SpaceMouse]

I have a 3% grade on my kids' Hogwarts layout. When I hook 5 modern cars to my old steamers (okay they have plastic wheels and axels) The Heisler and IHC 4-4-0 have no problem. The IHC 0-4-0 had a problem at first but a good cleaning of the track and it made the climb okay. The MDC makes it part way then starts to slip, The mogul is the smallest of the engines, but doesn't seem to lack for power. I'm guessing that the problem is that it doesn't have enough weight to maintain the friction it needs to overcome the weight of the cars.

Am I close?

[howmus]

You guessed right. The little mogul is not a strong pulling loco. It is also a hard one to find places to hide lead weights. I have added some lead weights to 2 or 3 locations and it increased its pulling capacity by 50%. I had to add little lead BBs in the cab and some small weights under the loco, even put some in the stack. 3% grade is a tough one to get it to do much more than a few cars. But then these by the 1920s they were pretty much relegated to branch line and switching duty and were not expected to be pulling a long consist of heavy freight.

[Anonymous]

Pretty Close.

MR released a article years ago about HO scale locomotive behavior. I imagine the MDC probably has a train moving onto the hill and when the "DRAG" (think of a force pulling backwards against the engine) over comes the "Force" (think of the pull on the front of the engine) then it will not be able to move forward.

I had a very steep hill one winter. My 18 wheeler was fully loaded. There is no question that I have the power and the strength to carry this weight. But... I got on that thin sheet ice halfway up and started slipping. I made it to the top but the weight was more than what was "holding on" (traction) to the road itself. I felt the truck "stagger" and threaten to slip backwards down the street. That was a bit exciting as there were people a few feet behind me praying that I dont stop. Never mind the angles of forces on that 5th wheel acting on the entire rig.

So when your engine staggers on the track and slips it's drivers it's telling you the load is too much. You can put a bigger engine or a shorter train. Or 2 or more engines. If none of these work then find more space and ease your grade. A customer at the LHS is doing just that. He tore out his heavy grades and started over with 1% grades.

I personally prefer to add engines. If you can share the load and get that train over the top then mission accomplished until the next hill. Sometimes I put a too big train on my BLI Mountain and have to either put the Mikado as a double header or get out the J1 2-10-4 or bigger engine to try to get the train up and over.

Doubling the hill or splitting that train up into two seperate trains is another option.

You can always add weight up to a point. If you put too much on then your motor will quietly burn up. I had a Tyco GP20 as a child which never had any kind of weight on that power truck. It derails when you try to start 6 cars on level track. I finally taped a brick from the back yard to the top of the engine and it did not derail for 2 laps. At the end of the 2nd lap there was a smell of burned motor.

My taste for large and capable motive power in the hobby stems from that day. The ultimate expression is my ABBA desiel unit (All powered) that is capable of any train on any grade at any speed. ( have yet to use it LOL)

[Big_Boy_4005]

MORE SAND!!!![swg]

[howmus]

QUOTE: Originally posted by HighIron2003ar

Pretty Close.

You can always add weight up to a point. If you put too much on then your motor will quietly burn up. I had a Tyco GP20 as a child which never had any kind of weight on that power truck. It derails when you try to start 6 cars on level track. I finally taped a brick from the back yard to the top of the engine and it did not derail for 2 laps. At the end of the 2nd lap there was a smell of burned motor.

Absolutley correct! A couple small lead wieghts added may be able to improve performance, but........ That little mogul is never going to pull a 50 car frieght train (well maybe down that 3% grade. LOL) It will be better to MU it to another loco and have it be a "helper" on a long freight than to push it capabilities too much. Mine is a good runner and (with some added weight) can pull 7 or 8 USRA coal hoppers and a caboose up a 2% grade. I wouldn't want to ask any more of it.