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Saturday, February 4, 2012

12-02-04 PHOTOS: S is for S-Motor

Yes its a Sesame Street theme this week, although instead of me teaching basic vocabulary and how to count to 12 you are all going to get a lesson on early New York Central electric locomotives and DC motor control systems. Sounds fun doesn't it? The framing device for today's lesson comes in the form of a number of locomotives "preserved" in a forested flood plain south of Albany, NY. These locomotives belonged (or still belong) to the Mohawk Chapter NRHS which received them from Amtrak and Conrail sometime around 1980. The collection includes an ex-NYC, ex-PC, ex-Amtrak Alco RS-3, an ex-NYC, ex-PC, ex-Conrail General Electric U25B and two former Ney York Central electric locomotives. While RS-3s and U25's are great, the two electrics are the real gems here because not only are they quite old, they also represent about half the total number of ex-NYC electrics that have been preserved.

The first of these electrics is the only surviving T-Motor, built as class T-3a in 1926 and represents the last batch of the second generation of NYC electric locomotive power. The second of these locomotives is S-Motor #100, which isn't just a member of the first class of New York Central electrics, but is in fact the prototype for the first class of New York Central electrics and because the S-Motors were the first class of independent main line electric locomotives ever built anywhere, #100 is the world's first main line electric locomotive.

Now I know what you're thinking, wasn't the first main line railroad electrification built on the B&O's Howard Street Tunnel in 1895? Well you would be right, but remember that that system was designed for electric assist of steam locomotives over a short stretch of steeply graded track with tunnels. Electrics would tow the steam engines, still fired up and making steam, through the short electrified section and then cut off to allow the steam hauled train on its way. The New York Central embarked on a much more ambitious scheme to both eliminate steam engine exhaust from its Park Avenue Tunnel and build a Grand new downtown rail terminal completely below ground level, which would make any sort of steam locomotive, under load or tow, completely infeasible. The S-Motors were the locomotives initially designed for this task with #100 being constructed in 1904, two years before the start of electric operations, in order to be throughly tested by both Alco (who built the locmotive) and GE (who supplied the propulsion system), on a test track in Schenectady, NY. #100 was originally assigned the class of L and the number 6000 while undergoing this testing. When it was time to enter service with 34 additional sisters #100's class was changed to T-1 and the number changed to 3400. After a deadly derailment on the second day of electrified service exposed a design flaw, #100's class was changed again from T to S and she was given the number she wears to this day.

Anyway, enough with the Wikipedia summary, its time to get onto some photos. You can see the whole set here (scroll down a bit), but I will actually urge you all to finish reading the remainder of the presentation here first. In fact you should start by viewing this little video tour of the two units. Inside some interesting items are obscured by darkness so reading the photo essay afterwards may help make things clearer.

So how exactlyis the world's very first main line electric locomotive being treated these days? Climate controlled shed at a major railroad museum? Complete interior and exterior restoration with a goal of returning her to running condition? No, one of the most historic locomotives in the world is being left to sit out in the elements on an isolated spur track located within the Hudson River floodplain.

So whats going on here? As far as I have been able to determine the Mohawk Chapter NRHS simply became defunct with their historic collection left to fend for itself. Fortunately their collection is not located where some landlord would care to threaten it with scrapping, but the condition of all these locomotives is hardly ideal.

There are some on again off again efforts to get people out there to at least stabilize the units and I have been told that they have been purchased by a heritage line in Massachusetts, but whomever the owner is getting these locomotives out of their current location is going to take some doing because even if the rail link to the former Conrail Albany secondary is intact it is not passable without a good deal of rehab. Whatever the state of the preservation efforts I wasn't going to pass up the opportunity to tell the story behind these amazing relics from the past.

The most apparent feature of the S-Motors are their short length, however these units were not designed for switching, but for hauling main line long distance passenger trains. The short length 39 feet was seen as an advantage as it was half the length of a locomotive and tender and trains could be doubleheaded without significant loss of platform space. However they entered service a number of tracking problems were identified and after 6 short years the units found themselves relegated to secondary duties as the new T-Motors replacement them.

The S-Motors were built with the 1-D-1 wheel configuration, which was soon upgraded to 2-D-2 after the 1907 derailment. The driving wheels were mounted on a rigid 4 axle frame with a suspension that was primitive to say the least. Another problem with these early electrics was that they made use of "bi-polar" electric motors. No this does not mean that the motors would be full of energy one day and sluggish the next, but that the DC motor armature is mounted directly to the axle with two static electro-magnet "poles" mounted to either side. This allowed the axle/armature combination to move in the vertical plain as the wheel moved over bumps in the track. unfortunately this axle/armature combination added to the units Unpsring mass that of course affected track handling and ride quality. As soon as improved technology allowed the motors to be reduced in size, electric locomotives switched to using geared motors and ultimately nose suspended motors. Also in this photo note the third rail pickup shoe fuse box rated at 700 amps.

Squeezed in front of the 4 driving axles on each end of the unit are two, twin axle pony trucks. These were originally a single axle truck, but after the 1906 derailment it was determined that the 1-D-1 design was not sufficiently stable at high speed. The single S-1 and her 34 S-2 sisters were modified to fit the new 2 axle design. The later 12 units of the S-3 class built in 1909 were lengthened by 4 feet to better fit it. Unfortunately, in solving the stability problem the extra pony axles took even more weight off the drivers and resulted in poor starting characteristics, especially with long trains. 

Another neat 1904 feature on the S-motors are the use of friction bearings on the main driving axles. Virtually unheard of today on modern railroads, friction, aka plain, bearings make use of a consumable oil supply to lubricate the action of a round steel axle rotating in a plain soft metal semi-circle. The oil would create a hydrodynamic boundary layer between the axle and the Babbitt metal of the bearing that would prevent the two parts from physically touching. The oil was applied to the rotating axle via a pad at the bottom of the journal box, which had a reservoir of oil it that was wicked up through the pad.

Well that's enough for the exterior of #100, let's head inside and see what we can find. The unique design of the S-Motor is sort of a rich man's Steeplecab, clearly inspired by the latter, but with a bit more fit and finish for its main line assignments. Compared to s Staplecab design, the cab space of an S-Motor was a lot more spacious to fit both a larger air compressor and a train heating boiler required for passenger service. Here we stand inside the cab area looking toward the #2 end. The S-Motor was designed for both a engineer and fireman with each position being on the accustomed side.

The control stand of an S-Motor should be familiar to anyone who has visited a trolley museum as the technology behind it is basically the same, only a little bit more fancy. Acceleration of the S-Motor is completely manual in that the engineer does not select an acceleration rate (as one does on more modern electrics), but instead has direct control over the amount of voltage going to the motors. In a DC motor control system rotational speed of the motor is dependent upon the voltage supplied. As the controller is advanced resistance is cut out of the circuit applying more voltage to the motor. The large number of notches on the controlled is to allow the engineer to make small adjustments to the voltage in order to create a smooth acceleration profile, avoid wheel slip and to avoid stalling the wheels and burning out the windings. Today such tasks are automated by camshaft controllers in DC propulsion systems or software in AC systems.

This control system would also make use of series and parallel wiring to increase efficiency by negating the need to dump power into heat through the resistance elements. With motors connected in series seeing the total voltage drop split between them so at 660 volts DC from the third rail, 4 motors connected in series would each see a voltage of 165 volts, two motors in series 330 and all 4 motors in parallel the full 660 volts. I am not sure how those modes are engaged, either automatically as one notches up the controller or via a separate mechanism, but such a system has been part of DC systems since Thomas Edison.

Also seen here at the engineer's station is the instrument cluster including gauges for air pressure and DC amps running through the motor. The S-Motors were fitted with 4 GE model 84 electric motors rated for 550hp maximum output giving the S's a total of 2200hp starting power, which put them towards the upper end of contemporary steam passenger trains in terms of power. The continuous rating was 1700hp.

The fireman's side is a bit more spartan featuring only an emergency brake valve. Note the New York Central green interior which later went on to become Penn Central Green.

If there was one thing that was not in short supply in these electrics it was heaters. The cab was full of resistance heaters which I guess implied that New York City still used to see "winters" back a century ago.

Heavy load auxiliary items like the air compressor and cab heaters were controlled from these breaker-switches.

Low load items like the headlights, sanding equipment etc, were controlled from a panel of push buttons in front of the engineer.

So I'll bet you are all still wondering what makes this little S-Motor go seeing as all you've seen are a bunch of air brake handles and heater switches. Well the electric propulsion gear in an S-Motor are stored in the 4 "saddle bags" located at the four corners of the body shell. It is actually rather anti-climactic how little interior space is devoted to making the whole thing run, which is a testament to the simplicity of early electric locomotive designs.

Now I don't have a wiring diagram of the S-Motor, but the general layout is easy to discern and if anyone knows specifics please feel free to leave a comment. From what I can tell the S-Motors were Lo-V type cars in that the full 660 was not routed through the engineer's control stand. Instead the controller operated high voltage contractors in the saddle groups. Here we see one of the primary contact groups, located above the feed in from the third rail shoe, that would have handled things like on/off and series/parallel switching. Note the sizable arc chutes which extinguish any arcs generated in the 660v switching process. Once stuck an electric arc will remain lit, acting like a giant plasma torch in the process, until the ionized conductive path through the air is dissipated. An arc chute pulls the arc into a long loop which dilutes the ionized air.

Here is a group of smaller contact groups and arc chutes located next to one of the primaries. These would be used to cut resistance in and out of the motor control circuit as the controller was advanced and retarded.  The resistance grids are actually mounted out of sight behind the control groups on the floor.  The class was recognized to have insufficient resistance capacity and if the engineer spent too much time between series or parallel the grids could overheat and melt.

Also in the saddles was the main breaker for the auxiliary systems. From the sign it was clear that this switch did not like being disconnected under load.

Moving up on the roof are a series of serpentine pipes that were part of the air compressor system and appear to be some sort of air dryers. There are two banks, one twice the size of the first.  I have seen some sources that identify these as the resistance grids, but original wiring diagrams prove the grid units are in the saddles and these pipes are in fact part of the air system. 

While we're up on the roof we can look down at the front of the unit and see the central raised longitudinal passageway and the two saddle bags on either side which house the control gear. Also visible are the filling ports for the sand system. It is worth mentioning that despite the neglect, #100's 1904 construction is withstanding the elements very well and the roof structure was completely solid and showed no signs of rotting through.

So with the S-Motor complete it is time to move on to the next generation of NYC electric, the T motor. T-Motor #278 was built in 1926 as class T-3a. The T-Motors themselves were built starting in 1913 to remedy the shortcomings of the S-Motors, specifically the lack of tractive effort and poor handling from the 2-D-2 wheel arrangement. The solution was to delete the non-powered trucks completely with an articulated B-B+B-B arrangement that also eliminated the long rigid wheelbase. However the motor technology has still not sufficiently progressed necessitating that the bi-polar design be retained. however with 8 GE 91-A motors of 380 hp each the T's power output was increased to 3040hp starting, 2500hp continuous. The steeplecab type design was also eliminated and replaced by more of a box cab with a distinct operating compartment at each end. The body shell was pointed to the truck assemblies at two points which resulted in two "porches", connected to the truck frames, extending from either end.

As you can see #278 is in a might bit better condition than #100 as she was given a new NYC Heritage pain scheme at some point after her retirement in the 1970's.

36 T motors were built in 6 batches, with the last batch, class T-3a, built in 1926 significantly after the T-2's were completed. The T's were faster than the S's with a top speed of 75mph and also developed almost 75% more tractive effort. They also sported such advances as forced air ventilation which gave these and following classes of NCY electrics louvered sides.

The truck and suspension units on the T's were absolutely ancient with a bolted structure and leaf springs. Here you can also see the substantial motor housing surrounding the axle as both axle and motor were one and the same.

Never assigned to switching service the T-motors were built with an retained cowcatchers throughout their service lives. The round cans on the porches are sand reservoirs.

So let's see what's going on inside #278.

 Right off the bat we find a stash of mini-pantographs in the #1 end of 278. These were fitted to all NYC electric locomotives to prevent gapping out in complex trackwork in GCT. The air operated pans would ride up to contact 660v rails mounted to the ceiling in strategic locations. While the full set of pans from both #100 and #278 were present, these are the sorts of items that can walk away if these units are not stored more securely.

Taking up most of the space in the #1 end operating compartment was the large tank for the oil and water used by the steam heating boiler on the other end.

The T's were a bit more OSHA compliant with the electrical gear being separated from the crew areas by wooden doors.

Inside the electric room we see the main contact groups up near the ceiling and down on the floor is the cooling blower. This blower either cooled both the electric room and the central traction motors, or just the central electric room, but either way it was driven by a fairly stout motor.

Looking back towards the #1 end bulkhead.

The air compressor is a bit more modern looking and isolated from the crew spaces which was probably a plus.

Here you can see some of the electric solenoids driving the contacts.

The number of electric contacts was far higher than in the S indicating a much finer degree of acceleration control.

Once again we need to play "spot the resistors" as they have been hidden away up in the ceiling hump. Mounted internally this is the primary reason for the forced air cooling which the S-Motor lacked.

In the #2 crew compartment the train heat boiler has been removed, but the space for it remains.

The control stand is virtually identical to that of the S-Motor, except there appear to be even fewer dials on the instrument cluster.

View of the engineer's position from the side.

Looking down on the T-Motor we finally know the reason behind that roof hump...its where the resistor grids go.

Also up top the remains of the steam heat boiler hump and two classic NYC non-sealed beam headlamps.

#100 seen from #278. The land behind the fence belongs to a power plant and the only way to get these units out by rail would involve backing them onto the plant property and then switching them onto the plant's abandoned rail connection to the Albany Secondary. The condition of that rail route is unknown at this time.

Also trapped with the electrics is former New York Central RS-3 8524, still painted as Amtrak #126, but a look inside the cab reveals all.

This RS-3 happens to be equipped for passenger service with a steam heat boiler.

8524's control stand, note the old NYC green paint.

Better call the Navy because I've spotted a U-Boat in the form of former Conrail unit #2510. The General Electric "Universal Series" was wildly successful for its time, raising the bar in what was expected in terms of horsepower and driving Alco into bankruptcy. Wen it came out in 1959 the U25B offered 500 more hp than EMD's premium GP20 and 750 more than their standard issue GP-9.

The cab design was sleek and futuristic, however some features like the built in water cooler and single piece picture window did not last.

Unfortunately the scrap metal thieves had already made a visit and their handy work was evidenced by the cut traction power cables laying on the ground. The high amperage cables are made from braided aluminum and such a target for thieves. Again I fear what other damage might be done to the really historic units #100 and #278.

Well I don't really think I have anything much more to say about this. If there is ever a donation campaign set up to properly protect and preserve these locomotives I encourage everyone here to donate to it least the units fade away into the marsh.

2014 Update:  Despite several rumors that these units have been purchased by one shortline or another they all are still sitting where I found them in 2012.

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