# Speed of RDC-1 vs. RDC-3? no issue, no problem



## Greg Elmassian (Jan 3, 2008)

It has been reported elsewhere that there was a difference in the speeds vs. the RDC-1 and the RDC-3.

I have a new RDC-3, and I have an RDC-1 that is about 5 years old.

They both have QSI DC/Airwire/DCC decoders installed with the brand new QSI RCS sound files (Thanks Josh and Loco Lee!)

I set them both to the same start speed (CV0 = 0).. the top speed is defaulted to max (CV5)

I ran them a few feet apart at speed steps 20, 40, 60, 80, and 126. My DCC voltage is between 23 and 24 volts.


There was very little difference in speed except at the max speed. Mind you that an RDC is top heavy enough that it can tip over on a 10' diameter curve at this speed, way above prototype speed.

I was all prepared to have to speed match them, but they are fine stock.

I consisted them and ran them around the layout and watched the couplers between them for who was going faster. It was a 50-50 thing, no problems except with Kadees close mounted, S curves are not great. I used the new Kadee "Prototype Head" Couplers, #907. I wrote this up on my site.


So that's good news to report.

I don't remember who reported a vast speed difference between the two, but mine are fine. Possibly there is something wrong with one of this person's locos, or maybe RDC's older than 5 years could have different motors.

Regards, Greg


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## San Juan (Jan 3, 2008)

Posted By Greg Elmassian on 03 Oct 2010 05:54 PM 

...Mind you that an RDC is top heavy enough that it can tip over on a 10' diameter curve at this speed, way above prototype speed.

How eerily true this statement is. I know you model the Santa Fe, and you probably already know about the tragedy related to Santa Fe's RDC pair. They overturned at excessive speed leading to the deadliest rail accident in California history.


Santa Fe RDC Wreck


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## Greg Elmassian (Jan 3, 2008)

Yeah, and luckily when they repaired M192, they added a baggage section, so the RDC-3 is a reasonable approximation. 

Regards, Greg


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## Madman (Jan 5, 2008)

Thanks for posting the article Matt. It was interesting reading.


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## aceinspp (Jan 2, 2008)

I recall several folks mentioning that the speed was higher in the RDC3. Good to hear very little difference. Well this is good news for me so when mine shows up I need not worry about the speed issue. Later RJD


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## Paul Burch (Jan 2, 2008)

My dad is probably one of the helmeted cops in the photos. He was there. All he said was that it was a mess.


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## GaryY (Jan 2, 2008)

Mine run fine as well. No noticeable speed difference between the RDC1 or 3 at all... (track power)...they look good running together. 

Gary


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## TonyWalsham (Jan 2, 2008)

Posted By Greg Elmassian on 03 Oct 2010 05:54 PM 
SNIP 
They both have QSI DC/Airwire/DCC decoders installed with the brand new QSI RCS sound files (Thanks Josh and Loco Lee!)
SNIP 
Regards, Greg 




Greg, Is QSI really using the initials RCS nowadays or is that simply misspelt RDC?


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## Greg Elmassian (Jan 3, 2008)

Hah! too many acronyms! 

Should be: 

They both have QSI DC/Airwire/DCC decoders installed with the brand new QSI RDC sound files (Thanks Josh and Loco Lee!) 

Sorry Tony, definitely a slip of the fingers... sometimes they type what they want to! 

Greg


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