[PRCo] Re: Nosing

[James B. Holland]

You Say It So Nicely!

So in theory, the B2 would provide a better ride on open prw than the 
B3  --  yet theoretically the B3 was designed Just For That kind of 
operation!!!!!!!


Jim__Holland



Boris Cefer wrote:

> The problem of B-3 is obvious.       The main (coil) springs are 
> higher on B-3 than on B-2, which means that the B-2 truck is laterally 
> stiffer than B-3.       In addition to that, on B-3 trucks the car 
> body rests on the truck frame at higher point than on B-2s.       The 
> B-2 truck bolster design is selfcentering and the weight of the car 
> body drives it to its lowest position (the result is automatical 
> dampening).       Also the tapered tread plus inadequate gauge 
> clearance (bad track) provides very good excitation for lateral 
> motions of the truck and whole the car body.
>
> Boris
>
> ----- Original Message -----
> From: "James B. Holland" <PRCoPCC at P-R-Co.com>
> To: <pittsburgh-railways at dementia.org>
> Sent: Thursday, January 27, 2005 6:41 AM
> Subject: [PRCo] Re: Nosing
>
>
>> Can be a variety of things.
>>
>> [[Snip]]
>>
>> It needs to be recognized that all  *hunting__is__Not__hunting*  --  
>> the differences in design between the B2 and B3 make for different 
>> performance on the same track. There was a portion on Church Street 
>> here in SF outbound between 17th and 18th downhill that was quite 
>> rough -- a B3 equipped car slammed back and forth sideways while a B2 
>> passed through with barely a disturbance. The Swing link possibly 
>> saved sideways motion on the car on a B2 truck as the truck itself 
>> moved back and forth on the uneven track -- the bad track was short 
>> enough that the motion was not transferred to the body. But the 
>> framing of the B3 truck would even get the spring pots moving from 
>> side to side which then transferred this motion to the body. The 
>> motion ceased when the car passed this brief section of bad track -- 
>> that would not happen with hunting -- hunting seems to intensify once 
>> begun until measures like purposely slowing are taken to alleviate same.
>>
>> This same type of situation is pointed out in the PCC books about 
>> Chicago B2s and B3s on rough track -- considerably sideways action to 
>> the B3 whereas it is hardly noticeable on the B2.
>>
>> Yes, the B3 was developed for open track but have said before that 
>> the B2 did just fine from a ride standpoint -- don't know if it was 
>> more problematic for maintenance. Would Dearly Like To Know what a 
>> ride on the interurban would be like with the *Original__B2Bs* ---- A 
>> Truly Superb Ride And The ONLY equipment I have ever ridden that 
>> aptly fit the description of *Riding__On__A__Cloud!*
>>
>>
>> Jim__Holland
>