Saturday, July 25, 2009

M.U. sockets complete

The connections to the M.U. sockets have been tested and are complete. That says all the M.U. connections are correct, and by extension the control stands are correct. The testing is done with a very old "ringer box" containing two 6 volt batteries and an electromechanical bell connected to some very long wires. The ringer box proved persnickety and of course needed repair of its own.

One twist (literally) in the M.U. wiring is the forward/reverse controls. Forward on one controller is the same as reverse on the other controller. Similarly, the pin in the M.U. wiring for "forward" on one end, must be the pin for "reverse" on the other end. As you can imagine, there's only one way to resolve this: "twist" the forward and reverse pins halfway down the car, so forward goes to reverse and vice versa. But how does it get back to normal for the next car? Heh - there's also a twist in the M.U. jumper cable.

Wednesday, July 15, 2009

M.U. wiring complete

Another big wiring job completed is the multiple unit wiring. This is the 12-pin jumper plug discussed earlier, and its numerous connections throughout the car.

The multiple-unit control plug carries signals which control forward/reverse, series/parallel and the various resistance points. This wiring must go to a remarkable number of places on the car. On each end, it goes to three places - motorman's control stand and also to two jumper plugs. The seventh connection is to the switch group which actually controls the car's motors.

These connections happen in three control boxes - one at each end and one in the middle of the car. The end control boxes connect to the motorman's control stand, two jumper plugs and the middle control box. The middle control box connects to the end control boxes and to the switch group. With 12 wires per connection, it gets pretty crowded in those boxes!

3rd rail changeover switch complete.

The wiring for the changeover switch is complete. You can see the parts which have been reused and which had to be made from scratch. It was not possible to obtain a solid piece of maple large enough, so the drum is a glued composite. The latches are a stock item from McMaster-Carr.

Friday, July 10, 2009

Third rail changeover switch

The 1005 is being restored to its 1934 configuration and appearance. In 1934, the Sacramento Northern operated on both overhead wire and third rail.

Electrically, it would be simplest to wire the trolley poles/pantographs to the third rail shoes at all times. However that is illegal and unwise. There must be a changeover switch that connects car power to the active one while isolating the other.

On the 1005, this is fully automatic. This is done with a pair of relays in the baggage compartment of the car. One relay picks up if power is present on the trolley wire. The other picks up if power is present on the third rail. If "trolley" is on and "third rail" is off, it energizes a wire which runs down to the changeover switch and says "switch to trolley". Or vice versa.

Alongside this relay box are four resistors. Two are dropping resistors for the two relays present in the box. The other pair are dropping resistors for the two wires going down to the changeover switch. One pair of resistors was fine (it was made of cartridge resistor elements which removed like a fuse.) The other pair was totally defective and new resistors had to be made. The order came in; it was wrong and had to be remade. They were further modified to replicate the original mounting style. This work was completed last week and the relay box and resistors are remounted in the baggage compartment.

The changeover switch is underneath the car. It processes each signal further. For instance if the "switch to trolley" signal is energized, it will switch to trolley, but only if it's not already in trolley, and only if the car is coasting (not motoring). If all conditions are met, the signal reaches a magnet valve, which applies air to muscle over a big rotary switch similar to a reverser. There is yet another interlock, which assures the switch will only operate when the car is configured for 600 volts DC (not 1500 volts DC).

As to the changeover switch itself, the restoration had a challenge.

Normally on a third rail car, all third rail shoes on the car are connected together electrically. Third rail shoes on one side are touching the third rail; on the other side they stick out, energized and dangerous. Crews in third rail territory are trained on this, and civilians are kept away. That is how SN 1005 was configured in 1934. The Key System bought the car in 1942. The Key used third rail to come over the Bay Bridge and into the San Francisco terminal, but they had low level platform loading. Passengers could easily touch a third rail shoe. So, Key required a more sophisticated changeover switch which isolated third rail shoes on each side of the car. They removed and scrapped the original changeover switch!

The correct changeover switch would have to be remade from scratch.

Changeover switches are very similar to reversers. The air motor, magnet valves and some other parts were scrounged from an old reverser. Outside of that, the changeover switch was built from scratch over the last two years, using the reverser on another car as a model. This was a considerable undertaking. It took about two years, and is complete. It has been installed and the heavy power connections have been made.

What remains is the small signal connections. At this writing, wiring has been pulled through conduit, between the changeover relays, the changeover switch, and the 600/1500 interlock.

What's in a plug? A challenging fabrication

Interurbans such as the SN 1005 frequently ran together in trains. The motorman worked the controls in the first car, and all the cars with motors responded in sync to his actions. This is done through "multiple-unit control", or "M.U." A control cable runs the length of the train, and jumps from car to car via plugs.

Ah, the lowly plug. We use plugs and sockets for so many things in our society, but who ever thinks about them? You need four to charge a cell phone. Nowadays plastic insulates the various pins. But what do you suppose they did in 1910?

There's a surprising answer. Maple.

The Western Railway Museum plans to M.U. the 1005 with other units, such as the 1020. The M.U. plugs on 1005 needed work. The copper pins were shot (fabricating them is another story!) and the maple insulators were in poor shape. How do you make one of these?

It's not as simple as you'd think. All the holes must have a very particular relationship to the index key. If any of them are off, the plug won't mate. And we had several to make. (they are four inches in diameter.)

Two approaches were tried. Rather than try to machine each plug individually, one of our machinists made a steel "cap" which could fit over the insulator. In this cap, he carefully drilled holes in the right places. A tedious job, but done once, it provided a jig that properly located the holes for any piece. A second approach was explored in the digital realm: software that would tell a CNC router how to cut the part out of a block of wood. Software incompatibilities slowed that project, and the traditional machinist won. Jawn Henry would approve.

The insulators were drilled, shouldered and tapped 1/4-20 for the pins, which screw in. Maple is a hardwood which accepts threads well. These pieces are almost 2 inches thick, and tapping them required special nut taps.

Maple is already an excellent insulator, but only when dry. One way to solve that problem is to boil the maple in paraffin, driving water out and wax in. However, in this case, the pieces were painted with Glyptal paint designed for high insulation value. The pieces really "drank up" the Glyptal. Bolts were screwed into the threaded holes to "mask" them from the Glyptal. The bolts came out easily.

Soldering wires onto the pins was the next step. For each plug location, the crew measured the distance to the junction box, and they cut 12 wires of this length. They tinned 12 pins then cleaned the threads of each pin, screwed the pin into the maple block, and soldered a wire to it. It wasn't necessary to mark which wire went to which pin; the wiring crew will ring those out later. No ribbon cable here!

The twelve wires were threaded through a cast iron rear cap, then inserted into the back of the cast iron housing and the rear cap was installed. The result is the picture you see at the top.

Click on any picture to zoom in. This work was completed on June 30.

Pilots repainted - June 20, 2009

One recent project is the repainting of the front and rear pilot. (some might call it a "cowcatcher".)

The pilots were removed from the car. They're too big for the beadblast cabinet, and sandblasting a large assembly out in the open is quite a dirty job. So the pilots were chipped by hand, it proved practical to remove all the old paint.

As always, the paint being used is Awlgrip 545 primer and Awlgrip topcoat. In this case the color is Super Jet Black.

Click on the pictures for a much bigger version.

This work was done about three weeks ago. The post is being done new because, well, it's a new weblog! Expect a few more back-dated entries to cover work recently done.

Thursday, July 9, 2009

Welcome to the weblog of the SN 1005 restoration, a project of the Bay Area Electric Railroad Association.

Sacramento Northern 1005 is an electric interurban car, one of the first acquired by the Association. It is a sentimental favorite among members, as it was prominently used in railfan excursions on the Key System and Sacramento Northern in the early days of the Association.

The car was stored in Oakland, but many of the excursions were in distant areas. This meant 1005 rode a lot of freight trains getting there. The 1005 is more fragile than a freight car, even though its couplers and brakes are compatible. This led to incidents of damage. The most severe was in 1962, when the center sills were badly bent. The Western Pacific Railroad moved it to their shop for repair, but after long study, considered the car too far gone.

Enter car 1020, another excursion regular. 1020 had been built as a trailer and converted to a motor. During a fan excursion in the 1950s, its electrical gear caught fire,and it was converted back to a trailer. The railroad offered both 1005 and 1020 in settlement for 1005's damage, with the notion that museum volunteers could strip the electrical gear from 1005 to remotor 1020.

The Association did not do that. 1020 remains a trailer. 1005 was used in limited fashion despite its damage.

And here, the phoenix story begins. In 1999, the Elliot R. Donnelley Family Trust offered $75,000 to restore 1005, and work began in earnest. The damaged frame sections were replaced. Restoration expert Glenn Guerra was brought on board. Virtually all of the woodwork below the ceiling was replaced. Windows, seats, mechanical and electrical work continues to this day. About $250,000 and 20,000 man-hours have gone into the project.

Most of the work is now done. The project is in its finishing stages. There are still a lot of interesting things going on, though. This weblog aims to document some of them.

Above is a picture of the car as of July 5, 2008.