Roller Bearings and the Y6-b

NW Mailing List nw-mailing-list at
Wed Oct 9 21:49:54 EDT 2019

Bill - 

You have to understand something about the 2100-2200 class Y engines.  At the end, they all had equal capability on the road.  All the improvements that came out on the newest ones were retrofitted onto the older ones.  Folks tend to memorialize the Y-6bs because they were the newest, but the Y-5s could do everything the Y-6b could do.

As far as speed was concerned, driving wheel RPM was what counted, and the 2100s were capable of sufficient RPM to allow them to run 45-50 MPH without damage to themselves or to the track.  At 50 MPH the Y’s drivers were turning about 290 RPM.  They were so well-counterbalanced that this was no problem.  At 290 RPM the A was running 60 MPH but, of course could perform much beyond that.

The only roller bearings the Y-6b had that the older ones didn’t have were on the back ends of the eccentric rods.

As for the 0-8-0s, they were not comvortable over about 25 MPH (ancecdotal evicence from folks who were familiar with them) because their lack of a stabilizing lead truck allowed them to nose back and forth, although their machinery was probably good for much more than 25.

- Ed King

From: NW Mailing List 
Sent: Wednesday, October 09, 2019 5:00 PM
To: NW Mailing List via NW-Mailing-List 
Subject: Re: Roller Bearings and the Y6-b

For that matter, the S1a did not get roller bearings of any kind. I assume roller bearing rods had some connection with speed, since the first applications industry wide were on passenger locomotives.

Jim Nichols

On Wednesday, October 9, 2019, 01:30:25 PM CDT, NW Mailing List via NW-Mailing-List <nw-mailing-list at> wrote: 

There's an old saying that goes "there are no dumb questions, only dumb answers."  But I'm afraid I am about to ask a really dumb question. 

We all know that the last five Class A locomotives had roller bearings on their main and side rods.  But the Y6-b continued to be built long after the last Class A.  Yet the Y6-b never had roller bearings on the side and main rods.  I assume the reason was because the Class A was a high speed locomotive while the Y6-b, being compound, was a low speed puller.

I'd be interested if any one knows the reason the Y6-b never got the roller bearing treatment.

Bill King
Arlington, Virginia
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