[PRCo] Re: Interurban PCCs_and_Models_Propulsion,_etc.

Tue Mar 29 13:07:38 EST 2005

So sad that I could not experience the Pittsburgh PCCs in regular service 50
years back.

B

----- Original Message -----
From: "James B. Holland" <PRCoPCC at P-R-Co.com>
To: <pittsburgh-railways at dementia.org>
Sent: Monday, March 28, 2005 11:31 PM
Subject: [PRCo] Re: Interurban PCCs_and_Models_Propulsion,_etc.

> Thank You, Boris  --  you have been a great instructor in the mechanics
> of PCC operation!
>
>
> Boris Cefer wrote:
>
> > Nice, Jim!
> >
> > Of course, to maintain the speed, you have to keep the pedal on the
steel
> > floor. If the car does not show any tendency to accelerate then, it
means
> > that all mechanical resistances are in balance with the tractive effort
> > provided by the traction motors and you are running just at the
balancing
> > speed for that particular track conditions and car load.
> > When you suddenly get on a downgrade, it represents a "negative"
> > resistance
> > which is added to the tractive effort and helps to accelerate the car
> > until
> > a new balancing speed is reached when the acceleration ends.
> > Even on a 6 % or 10 % downgrade the car has a theoretical speed at
> > which all
> > forces would get in balance and the car would stop acceleration, but
guess
> > it is far behind the motors' mechanical capabilities as they would fly
in
> > pieces.
> >
> > The service 17xx had possibly higher field shunting (?!) and was thus
> > capable of higher speed.
> >
> > At high speeds the dynamic spotting is too heavy because the accelerator
> > does not have enough resistors to put in the braking loop and keept the
> > dynamic current at a proper value, which is between 10 and 30 Amps for
> > each
> > motor group (20 to 60 Amps total current). Your equipment does not
> > ampermeters on driver's desk. We have! So we can observe what happens
> > in the
> > propulsion circuits and how heavy the spotting is at very high speed.
> > Before
> > additional field shunting was developed, it was whole not rare to see
200
> > Amps of spotting current on ammeter!
> >
> > B
> >
> > ----- Original Message -----
> > From: "James B. Holland" <PRCoPCC at P-R-Co.com>
> > To: <pittsburgh-railways at dementia.org>
> > Sent: Monday, March 28, 2005 6:07 AM
> > Subject: [PRCo] Re: Interurban PCCs_and_Models_Propulsion,_etc.
> >
> >
> >> I-F one doesn't keep the pedal on the floor, then spotting takes over
> >> and the car automatically slows. So it is necessary to keep the
> >> pedal there to maintain speed -- the indication with M11 being that
> >> the car was Flat Out Moving but the service car, PCC Interurban 17xx
> >> which had to stop for passengers, Still Caught Us!----THAT was my point
> >> (in the quote below!!) If the PCC is traveling downhill with power
> >> pedal floored then speed IS increased -- letting of power allows for
> >> spotting and this is quite heavy at such speeds and would definitely
> >> slow the PCC considerably -- experienced this Multiples Of Times here
> >> in SF through the tunnels.
> >>
> >> Son Of A Gun, John, you know that this same principle holds in models
as
> >> well, even transistorized throttles and DCC ---- Very Good Thing
> >> you mentioned this so it can all be tied together!! Turn the
> >> throttle of the Power Pack All The Way Up and we get full speed, half
> >> way slows the car down instantly, and off is Off -- Instantly!!!
> >> This Is Fun! :-) :-P :-D
> >>
> >>
> >> Transistorized throttles were all the rage in the 1960s and I had
plenty
> >> of time in Kodiak to study the model railroad magazines to design my
own
> >> throttle but never built it until out of the Canoe Club. The
> >> design allows for adjustment of acceleration *Rate*, Braking *Rate,*
> >> and *Coast* when power was released. Yes ---- the pot that
> >> controlled acceleration was turned completely Off and the model
> >> trolleycar kept right on rolling because of a capacitor in the
> >> circuitry -- the car gradually slowed but could go quite a
> >> distance. Braking was through a separate pot which drained the
> >> capacitor more quickly -- the pot just chose a *Rate* of
> >> deceleration with increased movement in the pot choosing a faster rate!
> >>
> >> I built a very crude set of foot pedals to operate the models and could
> >> do so for multiples of hours without a break -- NO 10-hour limit
> >> behind the controls!!!!!!! The deadman cut power to make an
> >> instant stop IF needed but I never used that feature but Had to keep
the
> >> deadman depressed to have power! Boris says this is not true of
> >> PCC operation, and I certainly accept his critique, but it *seemed*
> >> that it was possible to build up speed with an All-Electric and then
> >> back off on the power pedal to just engaged to maintain that speed --
> >> this way one could make a quick transfer to the brake pedal if
> >> needed. Could not do this with the transistorized throttle and
> >> this disappointed me, but in reality, the transistorized throttle did
> >> mimic all aspects of All-Electric PCC acceleration, coasting, and
> >> braking quite admirably.
> >>
> >>
> >> I had a contactor in the overhead to operate my track switches ala the
> >> prototype -- coast through the contactor and the turnout remains //
> >> sets for straight through -- hit the toggle on the control panel when
> >> the trolleypole hits the contactor and the turnout sets // remains in
> >> diverge! Worked like a charm!!
> >>
> >>
> >> DCC has the *Rate* features built into the decoders but the advantage
> >> here is that the Overhead voltage is constant -- Always On at maximum
> >> setting! This alone is an advantage, esp at lower speeds to allow
> >> the equipment to roll smoothly without jitters from contact problems at
> >> low voltages. Contact can always be a problem but the constant
> >> voltage lessens it. It is also possible to have the PCC bell,
> >> interurban horn, compressor sounds for Air-Cars operated through the
> >> decoder and it is also possible to turn on and off the roof light, head
> >> light, interior lights separately!!!!!!!
> >>
> >> Stationary or mobile decoders can operate various wayside items to
> >> control turnouts, animation, lights and a whole host of other items.
> >>
> >>
> >> Computers can be connected to the *RR* to control the equipment,
> >> signals, turnouts etc. - one, any combination, all. Computers can
> >> have full control of the RR and total manual control of the RR is also
> >> possible while the computer controls signaling and other items.
> >> Any combination of automatic // manual control -- i.e., computer
> >> operating some equipment and humans operating other equipment -- is
> >> also very possible. Very software intensive but I have basic
> >> outline of what I personally would like to do in this area and Chubb's
> >> books on Computer/Model Railroad Interface (C/MRI,) both the basic
> >> description and heavily technical volumes which will help to make this
> >> all possible. Have the computer operate several cars on one line
> >> while a human(s) tries to keep a schedule on the same line! Email
> >> lists also help with the learning curve.
> >>
> >> But DCC gets more interesting each day with all the new developments
> >> -- much like computers for the last couple decades. Transponding
> >> and Bi-Di are now quite possible but still in the development phase and
> >> this could lessen the need for computer control or aid the computer in
> >> identification of equipment and location. Radio control is all the
> >> rage because it allows for freedom of movement of the operator but
> >> suffers from interference of Sloppular__Phones as the frequency used
> >> by both overlaps! Absolutely Detestable Thought that one of these
> >> ({[phones]}) could take control of a model!!!
> >>
> >> Twins were completely enthralled with lrvs and I built each a Boeing HO
> >> model using slides of each of them at the controls of a prototype
Boeing
> >> as the actual ends of the model -- looked decent enough. Sides
> >> were plastic and were heated in the oven at very low temp, then pressed
> >> over a wood block which I had carved to the basic lrv design with
> >> fishbelly coutour -- wider at belt rail than at roof line and
> >> skirting -- with curved taper to the ends. These were Christmas
> >> presents and this caused quite a bit of tension as I had to lock myself
> >> in my room to do the work!
> >>
> >> Both lrv models could be operated simultaneously and individually by
> >> each of the Twins as the lrvs picked up power from the overhead but
> >> grounded through only one of the two rails -- right rail for one lrv,
> >> left rail for other lrv. A contactor in the overhead as the model
> >> entered the single track section from either direction activated a
> >> simple switch machine with DPDT contacts to change the wiring alignment
> >> in the rails to keep the right and left rails aligned with the
equipment
> >> direction -- without this the lrv would be controlled by the other
> >> throttle in one direction along the single track. If one of them
> >> ran the signal while the other was in the single track, the latter took
> >> control of both models ---- and boy, the fuss this created!
> >>
> >>
> >> Including several photos which the email arranges in its own order
> >>
> >> URLs should be at the very end of the email:::
> >>
> >>
> >> 1.>-- Prototype Boeing lrv shells
> >>
> >> 2.>-- Construction of HO layout for Twins.
> >>
> >> 3.>-- HO lrv body shells
> >>
> >> 4.>-- Completed lrvs on upper loop -- contactor for acting switch
> >> machine for electrical circuit in single track can be seen in overhead
> >> of lrv in the back.
> >>
> >> 5.>-- A view into "Downtown!"
> >>
> >>
> >> Before transferring to Kodiak in 1964, I had written to SLCCo and Clark
> >> -- SLCCo sent me drafting plans for all PRCo PCCs as 0.75"=1'0"
> >> while Clark sent 1/4-Size(3"=1'0"!) prints of trucks for air cars and
> >> All-Electrics, both the B2 and B2B -- some drawings included of
> >> various parts full size!!!!!!! My dream was to have a 1"=1'0"
> >> PRCo PCC Interurban -- a 1.12 model -- or several if at all
> >> possible -- And I Am Still Hoping For This.
> >>
> >> If anything is scaled down to 1.12 size it is done in 3-dimensions --
> >> Length, Width, and Height! And if it was possible to shrink
> >> something like this, then it can be claimed that the weight of the
> >> prototype reduced to 1.12 size would be 1/1,728. A 1.12 PCC would
> >> weight almost 21-pounds; each truck would be *aprox* 5-pounds --
> >> hold a 5-pound bag of sugar in your hand for reference! The body
> >> with all gear would weigh about 10-pounds and the truck, B3 Of Course,
> >> could be sprung ala the prototype for some very interesting action on
> >> scale prw!!!!
> >>
> >> The NMRA provided formulas to determine the motor characteristics I
> >> would need to power this car -- one motor/axle ala the prototype --
> >> and I had information from Pittman on the motors I could use. Size
> >> is a problem -- motors would fit trucks with barely any room to spare
> >> -- and body bolster would need modification to fit the motor in.
> >>
> >> In Those days, control would be through typical Model Aircraft radio
> >> control with various servos controlling apparatus on the
> >> equipment. I could actually have a rotary accelerator by using a
> >> rotary rheostat but would have used a separate one for dynamic braking
> >> as the control features would be too complicated using one for
> >> both. Actual Dynamic Brakes would have slowed the car --
> >> magnetic track brakes could be used for emergency -- and a lockout
> >> relay would prevent the friction brake from applying until the dynamic
> >> had faded. RCA provided me with sample circuits for controlling
> >> the lock out relay and for charging the onboard battery which would
only
> >> be used if the trolleypole dewired to prevent the drums from applying
> >> until brakes had been applied -- otherwise all power would be received
> >> from the overhead.
> >>
> >> Today, however, DCC decoders Are NOW available to control the amount
> >> of current needed to run such heavy equipment -- I would most likely
> >> use separate ones for acceleration and braking. Hope I am able to
> >> make this happen!
> >>
> >>
> >> -- Attached file removed by Ecartis and put at URL below --
> >> -- Type: image/jpeg
> >> -- Size: 225k (230632 bytes)
> >> -- URL :
> >
> >
http://lists.dementia.org/files/pittsburgh-railways/Boeing_lrv_shells.jpg
> >
> >>
> >> -- Attached file removed by Ecartis and put at URL below --
> >> -- Type: image/jpeg
> >> -- Size: 144k (148437 bytes)
> >> -- URL :
> >
> >
http://lists.dementia.org/files/pittsburgh-railways/HO_construction_1978xxxx
> > _JBHolland.jpg
> >
> >>
> >> -- Attached file removed by Ecartis and put at URL below --
> >> -- Type: image/jpeg
> >> -- Size: 92k (94795 bytes)
> >> -- URL :
> >
> >
http://lists.dementia.org/files/pittsburgh-railways/HO_lrv_BodyUnit_197910xx
> > _JBHolland.jpg
> >
> >>
> >> -- Attached file removed by Ecartis and put at URL below --
> >> -- Type: image/jpeg
> >> -- Size: 111k (114595 bytes)
> >> -- URL :
> >
> >
http://lists.dementia.org/files/pittsburgh-railways/HO_lrvs_UpLoop_19791225_
> > JBHolland.jpg
> >
> >>
> >> -- Attached file removed by Ecartis and put at URL below --
> >> -- Type: image/jpeg
> >> -- Size: 285k (292741 bytes)
> >> -- URL :
> >
> >
http://lists.dementia.org/files/pittsburgh-railways/HO_PCC_Key_19791225_JBHo
> > llant.jpg
> >
> >>
> >>
> >
> >
> >
>
> --
> Jim__Holland
>
>
> I__Like__Ike.......And__PCCs!!
>
> down with pantographs ---- UP___WITH___TROLLEYPOLES!!!!!!!
>
>
>