Donner Pass Observation

[GaryG]

Hi

I've always wondered why I have so much slippage on the Westbound grade and always assumed snow and curvature physics were the cause.

I set up test trains with one SD40 and twenty coal hoppers, one train loaded and one train empty, I also used good weather. I did at least prove to my satisfaction that the loaded cars did add what I thought to be an appropriate amount of weight to the train by the way they handled so that's good info to know.

I could get about five miles or so up the hill with both trains but then both start doing strange things similar to what I've seen before but never noted the location.

Near 39.29293 -120.27228 there is a long curve, almost 180 degrees. The grade before, through and a bit after is 0.0% so one would think there would be no problem but about half way around, for no reason as far as I can tell, the speed drops and with the loaded train the rail is so slippery that I can't go higher than about Run2 without slipping, even with sanding. Up to that point there was no slippage even with lots of power at low speeds.

It acts as if the rails are greased. Could this perhaps be a track rule problem?

Any ideas?

GaryG

[PapaXpress]

Be sure you are not using one of the dodgy engines they created for DP. It was designed to fail periodically.

[GaryG]

I did use a "real" SD40; I am familiar with the dodgy ones with the script that almost guaranteed that all dodgy locos would fail long before a scenario completed.

When I did my last test, I used the empty twenty car train. Once I started the climb, I left the Throttle in Run8 and used individual car brakes to hold at or close to the 25MPH track speed. I left it in Run8 to see if it would slip. On the 2.8% grades, none or or just a bit of braking was required and on the level, ten or eleven brakes applied held the speed until I rounded that curve and suddenly the train suddenly started slowing even though it was a 0.0% grade and I was in Run8. I released all the brakes, and it still slowed and started slipping even at lower throttle settings. I could see the start of the next grade section but was still on level track.

Makes no sense at all, I had already climbed two 2.8% grades and some level between and saw absolutely no slipping. Up until this curve the train had handled completely as I expected it to.

I think there are other locations on this route with similar behavior, this is the first I've sort of pinpointed.

More tinkering to do to see if I can determine a possible cause. Perhaps I can define an activity that starts around this strange part of the RailWorks world.

GaryG

[GaryG]

I give up, no consistency with what I'm experiencing.

Prior to the slipping I can run at full power at any track speed, on a long 2.3% grade or on a 0.0% flat area without slipping. With my last attempt, the slipping started prior to the 180 degree curve.

Once the slipping started with the train at about 20MPH, Run2 was slipping with no sand and with sand Run3 would slip.

I tried a save once the slipping started to see what would happen by restarting from the save. All that got me was a SBHH when I tried to 'Continue' so I'm thinking that something within RW is actually crashing and causing the weird problems I've seen on the Donner Pass hills. The only conclusion I've sort of made is that the longer and heavier the train, the more chance I will see this glitch. Oh well, lots of other routes run fine. These are the first SBHH's I've seen in quite a while so I don't think I have a bad installation.

GaryG

[Bananarama]

Just a stab in the dark - Could you try the same with an F-Unit or an EC44? If neither produces this problem, then it's likely the SD40. Otherwise, then I would wager the track, track rule, or the route itself is faulty.

[GaryG]

Hi Hack,

I've seen the same slippage with the Dash locos as well.

The only thing that I think might be a constant is the slipping always seems to start in a curve and the train feels like brakes have applied. Of course, now that I've said that, the next test will have it happen on a straight ;-)

I'll try to spend some time next week trying to figure out what might trigger it.

GaryG