Intermountain F3 - Geared to Run Slow?

Model Railroader General Discussion (Model Railroader)
1

I have two pairs of Intermountain F3s, one is an AA consist and the other is an AB consist, both equipped with QSI sound decoders.

These consists both run smoothly, but at top speed they are slower than most of my other diesels. Does Intermountain gear their diesels to run slowly?

Anyone else notice this?

Rich

2

Rich,

I have never really noticed any big difference with my DC powered Intermountain F units compaired to my Genesis F units - but simple test might be in order?

I will get back to you.

Sheldon

3

Thanks, Sheldon.

Rich

4

It may not be gearing as much as the CV setting for top speed. Down load the QSI manual if you haven’t and find out about the CV’s for start, mid and top voltage. With DCC you can set the top speed so even at full throttle, the loco wont be doing 110 scale MPH. Joe

5

Are you running DC or DCC? The answer changes depending on what you are using. In DCC it’s the settings (ask someone who uses DCC - I’m shutting up now). In DC the full electronics package with sound can act like a big resister, but then you would be starting act 6 volts to go with the low top speed.

6

Running in DCC.

I will check those CV settings.

Rich

7

Rich,

Sorry to be so long in getting back to you.

I took several Intermountain F units, and several Genesis F uints and did some speed comparisons.

The Genesis units started a little sooner, and had a very slightly higher top end, at my 13.8 volt max power, but overall they ran the same speed, especially in the mid range.

In fact they ran so well I lashed up several mixed sets and pulled a passenger train around the part of the layout that is operational - they actually MU’d just fine together - they are that close.

Remember these are pure DC versions, no decoders, factory DC lighting, and running on my Aristo Train Engineer throttles.

So my sense is that it is a decoder issue.

Sheldon