Doodlebug Doorway

Gregg Wolfersheim sends us some more photos of his work on the UP doodlebug:

A little more progress on M-35. I found a wood insert in a window post that was rotted out. Of course it was behind the divider wall! I had to loosen all the mounts that hold the wall and shift it a few inches to get at the offender. Here you can see the new piece mounted, with the wall back in position.

After fixing the window post, I started to reassemble the divider wall and found another problem. The piece over the doorway was also rotted. It is a three piece assembly, but the inner part was bad. You can see the missing part nearest the camera.

Here is the new piece of aspen next to the old part.

After some work with the table saw, I've got the offset and tongue and groove edges matched up. Next I reassemble it with the trim pieces after stripping the paint and old varnish off of them.

The whole assembly is now back in above the doorway. In this photo we're looking towards the rear of the car. The adjoining walls have had their paint removed, but not the varnish, yet.

Reverse Engineering

While looking through some old papers, I came across a sheet with calculations I made several years ago, trying to figure out what actual resistances were used in the control system for the wood cars.  It's rather cryptic, so I reformatted it and added some explanations.  This should apply to all CA&E cars with GE-66 motors.

We start with the data for the grid elements used on these cars, taken from the GE data sheet:

Grid Type	Resistance (ohms)	Current Rating (amps)
4	0.023	75
6	0.038	60
7	0.047	55
8	0.059	50

I might note that because our grids are old and rusty, the actual resistance may be higher than the nominal value.

Then here is the resistance part of the motor circuit schematic.   R1 through R7 are labels both for the contactors, and for the resistances between them.  It should generally be evident from context which is which.  All of these contactors are connected to the 600V supply when the trolley contactors are closed.  RX is just my name for a junction point in the circuit.

The next table lists the arrangement of grid elements in each box, the total resistance of each group, and the effective resistance for the resistors shown in the schematic.

Box	Grid Arrangement	Connections	Resistance (ohms)	Resistor #	Total Resistance
1	8A10	R1-R3	0.590	R1	0.590
	6A8	R3-R4	0.304	R3	0.456
2	6A4		0.152
	4A14	R4-R4A	0.322	R4
3	6A18	R2-RX	0.684	R2	0.682
4	4A10	R4A-RX	0.230	R4	0.552
	7B8	RX-R7A	0.094	R7
5	8A7	R5-R6	0.413	R5	0.413
	6A5	R6-R7	0.190	R6	0.190
	7B6	R7A-R7	0.071	R7	0.165

Note that some of the resistors are split between two boxes: R3, R4, and R7.

Now, starting with the control sequence, we can calculate the total resistance on each point as the controller is advanced.   I also calculated the percentage by which the resistance is decreased on each step.  Points 1 through 5 are series, 6 through 10 are parallel. 

Point	Contactors Closed	Resistors in Circuit	Total Resistance (ohms)	% of Previous Point
1	R1	R1+R3+R4+R7	1.76	--------
2	R1,R3	R3+R4+R7	1.17	66%
3	R1,R3,R4	R4+R7	0.72	61%
4	R1, R3 to R5	(R5+R6)║(R4+R7)	0.33	46%
5	R1,R3 to R7	None	0	0
6	R2	R2+R7	0.85	--------
7	R2 to R4	(R2║R4) + R7	0.47	55%
8	R2 to R5	((R2║R4) + R7) ║ (R5+R6)	0.27	57%
9	R2 to R6	((R2║R4) + R7) ║ R6	0.135	50%
10	R2 to R7	None	0	0

+ means “in series with” ║ means “in parallel with”

So starting with the question "Why in the world did this have to be so complicated?" we have a least a partial answer.  This was really an interesting problem to work out.

Our Newest Members

And in personnel news, we'd like you to meet the newest members of the Hicks Car Works team: Noah (L) and Vivian (R).  Noah has ridden the Grand Canyon, and Vivian has ridden a streetcar, but this was their first trip on the 309.  And of course they enjoyed it -- who wouldn't?  Their main duty as team members for the next few years will be nagging their parents to come out to IRM more often.

Traction Day Photos from Chuck Amstein

Our staff photographer provides us once again with an excellent selection from Saturday.  The usual dire threats of legal action against unauthorized reproduction apply.   Any captions are mine.

And Chuck's video is at this link!

First, we always need a picture of the crew.

"I don't know, maybe there's a train over there you guys could run."

Mark Hoffman on the IT train.

"Hmm, I wonder what makes the wheels turn?"

Dan Buck on the 319.

Zach Ehlers on the North Shore train.

Before the Automobile

This weekend's theme has been "Before the Automobile - How People Got Around Before Cars Were Popular" and yesterday's main emphasis was on interurbans.  We had three three-car interurban trains in operation, as well as another single car, several streetcars, and the steam train.

Here's the CA&E wood car train in the yard: cars 309, 36, and 319.  Chris and Dan Buck took turns as motorman and engineer, and Frank and I were trainmen.

And then the North Shore train: cars 160, 714, and 749. 

The Illinois Terminal train, 277, 518, and 234 pass the CA&E cars.

West Towns 141 was in operation on the loop. 

Then the 1630 passes by. 

South Shore cars 34, 40, and 1100 were on display at 50th, along with the Charles City engine.

And in switching, the 451 was moved up to the west end of track 62 temporarily.

And we also have some great photos from guest photographer Chris Buck: