[PRCo] Re: Interurban PCCs_and_Models_Propulsion,_etc.
James B. Holland
PRCoPCC at P-R-Co.com
Sun Mar 27 23:07:50 EST 2005
> John Swindler wrote:
>
>> Concerning M11, Jim, the power pedal might have been to the floor,
>> but at the balancing speed, that doesn't do any good - except to
>> maintain the car's speed at the balancing speed of the motors.
>
>
> James B. Holland wrote:
>
> Thank You for mentioning this, John -- don't know how I could have
> missed this fact! :-D
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!
>> It's not the car's that have a balancing speed. It's the motors.
>>
>> John
>
>
> Let me restate this to make my point clear ---- After reading the
> books I was under the impression that ALL PCCs were wired the same,
> thus their motors would deliver a maximum of 42-mph balancing speed on
> level tangent track, no // minimum load. Thus ALL PCC Cars would
> operate at the same speed.
>
>
> Jim
>>> From: "James B. Holland" <PRCoPCC at P-R-Co.com>
>>> .......M11 took speed extremely well with little vibration, however
>>> -- rode a charter out on Library and the power pedal was flat on the
>>> floor unless it was absolutely necessary to brake. Very Interesting
>>> that the 17 on Library caught up to us at Castle Shannon Inbound --
>>> motorman on the charter thought it would even though we were moving
>>> at break neck speed with M11.
>>>
>>>
>>> Jim
>>
Jim__Holland
I__Like__Ike.......And__PCCs!!
down with pantographs ---- UP___WITH___TROLLEYPOLES!!!!!!!
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