boblenon wrote:So today 7405 joined the list of locos that I have seen suddenly take off when track power is turned on.
I frequently see locomotives "lunge" forward (or backward; arbitrary) when the power is put on, but not take off. Interesting.
Last week [...] I [...] saw Lakawana 954 do it twice
[...]I just tested it [...] when I turned that on Mike's new CSX 2738 tried to speed off [...]. This appears to not be 100% reproducable either
The only thing I can think of is that 7405, 2738, and (I believe) 954 are all P2K. As such, I'm pretty sure they all have the same decoder installed (NCE's DA-SR).
I'm going to guess the problem is being caused by one of two things:
- A problem with this particular decoder, or (more likely)...
- The decoders are set to run on DC (if they were to be placed on a DC layout)
All DCC decoders have the ability to run DCC-only or DC/DCC in this way. There is a CV that controls whether they will respond to straight DC which is probably set for DC/DCC by default (IIRC).
I have heard about locomotives taking off like this when they are set for DC ops like this. Thus, in the past, I have disabled DC on all decoders for safety; should DC be applied to the tracks for some reason, the locos shouldn't take off.
I'm guessing that we're getting a spike of DC to the tracks on startup, and the engines with DC enabled are the ones that jump and/or take off.
I haven't disabled DC on the 2738 yet, so that could explain its behavior. I don't think I did it for 7405 or 954 either, so this is the most probable cause.
I'll take a look at this Tuesday night...