Electric Locomotives and Quill Drives

[rcdrye]

Ed Burns (NP Eddie) asked about the difference between various electric locomotive motors and drive systems, especially after a question about quill drives.  Here's a start - feel free to add.

Frank Sprague's quill drive - also known as bipolar

In this design, the motor is mounted around the axle.  The motor shaft is hollow, with a wheel on each end with "quills" sticking through holes in the actual drive wheels.  Springs on either side of the "quill" cushion the motor start.  The field windings are carried in the locomotive frame on either side of each axle.  Examples include NYC's original S-motors and Milwaukee's Bipolars.  A little hard on the track it still made for long-lasting locomotives, with NYC's lasting into the Conrail era.  As far as I know, all quill/bipolar direct drives were DC.

Geared Quill Drive

  In this setup a hollow quill is equipped with a drive gear on each end.  By using the gear drive the weight of the armature is carried as sprung weight instead of unsprung resulting in improved ride characteristics.  New Haven EF-1 was the main version of this, though PRR tried it again in the 1930s.  AC and DC worked equally well.

Dual motor geared quill

This is the familiar PRR P5, GG1, New Haven EP2, EP3, Milwaukee EP-3 and CUT/NYC P-motor design with two relatively small light motors diving each quill gear.  Pioneered in NYNH&H's 1911 experimental 069, it became one of the dominant designs prior to the development of Motor-Generator designs in the 1920s and rectifier designs in the 1950s.  AC and DC examples.

[Deggesty]

I have known of the Milwaukee's bipolar locomotives for many, many years--yet I never saw (perhaps I did not look in the right place) any description of the motors. I een asked my brother who finished college with a degree in electrical engineering in 1952 for a desscription--and apparently The Citadel did not think it necessary to cover that, for he was unable to answer my question.

Thanks for the description.

[rcdrye]

I'm not entirely sure either the S-Motors or the Bipolars really had quill drives.  Most sources indicate that "the motor used the axle shaft as the armature".  NYC's T-motors had the same drive but a different layout.  All of them survived into the 1960s, the T- and S-motors into the 1970s in regular service.  Only the arrival of the ex-Niagara Junction motors in 1978 ended the S-motors service.

There were european versions (DB E91/191) and at least one UK design) that used axle mounted quills motors.

Some examples of single motor geared quill drives are PRR's B1 switchers and L6 freighters. Swiss Federal Railways had the Ae4/7 (and some other SBB classes).  The Swiss units lasted into the 1980s in regular service but the PRR L6 units were not considered particularly successful - being poor enough performers that only one of the thirty Lima-built L-6a class ever got any electrical equipment.

[daveklepper]

But the B1 switchers were successful, 0-6-0's or 0-C-0s.  Those built for the LIRR worked only at Bay Ridge and at local freights to Fresh Pond Jc., PRR's at Penn Station, Sunnyside, 30th Street and for a while at Broad Street, Baltimore, and one at Wilmington.  A very neat compact design, not completely symmetrical.  Never knew the purpose for extension of the outside underframe in one direction.

Washington Union Station used B6 0-6-0 slope-backed tender steam switchers, PRR design, but labeled Washington Union Terminal in gold letters on three lines on the tender.  Headlight on the sloped back, of course.

The local LIRR freight Bay Ridge - Fresh Pond Junction interchanged with the South Brooklyn at Avenue H and Macdonald Avenue.  The steeply greaded curved connecting track had 11000V catenary up to a point, then there was a gap of about 20 feet, no more, and then the 600V DC of the Macdonald Avenue streetcar line.  There were two signs hanging from the wires, one read "600V Motors Stop Here," and the other "11000V Motors Stop Here."

I once saw a train of subway cars being delivered on this connecting track, R-10s.  But the LIRR used a diesel to push the cars up the grade.  South Brooklyn did couple on a trolley-pole (and third rail) steeple-cab.

[RME]

rcdrye

Frank Sprague's quill drive - also known as bipolar

Guys -- no, no, no, NO.

Bipolar was BATCHELDER's invention, and yes, the armature was rigidly fixed on the axle and moved up and down with it (increasing the unsprung mass).  The pole pieces on the stator were aligned like a pedestal to permit the axle to move vertically within the gap.  There are good pictures in contemporary magazines and in Burch's Electric Traction for Railway Trains (of 1911).

Edit: There is a good discussion ... by Batchelder himself ... in the General Electric Review (v.17) which can be downloaded via this link.  Select the PDF option in the list at right.  The special review of railroad technology was November.

[RME]

daveklepper

Never knew the purpose for extension of the outside underframe in one direction.

Unless I am mistaken, it's because the Rats were originally intended to be used in married pairs.

[rcdrye]

The 1905 EP-1 built for NYNH&H had a gearless quill drive with a hollow armature surrounding the axle.  The 1909 experimentals 071 and 072 were the first ones with a geared quill.  Both the bipolar and gearless quill designs suffered from high unsprung weight.  The side-rod design ("Bull Moose" was one nickname on the NH for 068 and 070) was one way to get the weight sprung and to raise the center of gravity to help tracking. In the end 069's pattern with the dual drive geared quill won out.

It's interesting to look at NYNH&H's 1908 side-rod experimentals, contemporaries with PRR's DD-1, to see that motor and drive design was anything but fixed in the first decade of the 20th century.

[RME]

rcdrye

the PRR L6 units were not considered particularly successful - being poor enough performers that only one of the thirty Lima-built L-6a class ever got any electrical equipment.

I don't think it was so much they were 'poor performers' -- they did outlast almost all the 'singleton' classes -- as they were improperly sized.  PRR (in the quality spirit of "design" that brought you the L5, which WAS a poor-performing fiasco) seemed to have decided that bidirectional "equivalents" of its E, K, and L classes were the appropriate sizes for electric motive power units.  (I have had the sneaking suspicion that the DD2 and T1 are similarly 'conjoined' design efforts.)

What better for freight work than an electric Lollipop?  Problem was that the money spent on these would be far better used on more GG1s, by then a costed-down design with far more stability, and a further problem was that all those P5s that were not particularly good in high-speed passenger service were doing the rest of the freight job better than the L6s could.

The sad thing, perhaps, was that the 29 completed (with Government subsidy help) Lima carbodies - reportedly so complete they looked like operable locomotives - couldn't be repurposed into anything the PRR could use, in 1935, 1938, or on the proposed extension to Pittsburgh - too big and rigid to switch, and I think with the wrong power increment when MUed.

[wanswheel]

https://archive.org/stream/cu31924003628603#page/n7/mode/2up

[RME]

Why just the reference when you can download your own copy of the book?

Internet Archive can provide you one, too -- click on 'Alternative Formats' and then select the PDF option if you don't want to read it online.

[rrlineman]

you forget that 3 L6's were powered. 2 from Altoona with GE gear. they were considered enlarged P5's by the mechanics at Wilm Shops.

[daveklepper]

[quote user="rcdrye"]

Ed Burns (NP Eddie) asked about the difference between various electric locomotive motors and drive systems, especially after a question about quill drives.  Here's a start - feel free to add.

Frank Sprague's quill drive - also known as bipolar

In this design, the motor is mounted around the axle.  The motor shaft is hollow, with a wheel on each end with "quills" sticking through holes in the actual drive wheels.  Springs on either side of the "quill" cushion the motor start.  The field windings are carried in the locomotive frame on either side of each axle.  Examples include NYC's original S-motors and Milwaukee's Bipolars.  A little hard on the track it still made for long-lasting locomotives, with NYC's lasting into the Conrail era.  As far as I know, all quill/bipolar direct drives were DC.

Geared Quill Drive

  In this setup a hollow quill is equipped with a drive gear on each end.  By using the gear drive the weight of the armature is carried as sprung weight instead of unsprung resulting in improved ride characteristics.  New Haven EF-1 was the main version of this, though PRR tried it again in the 1930s.  AC and DC worked equally well.

Dual motor geared quill

This is the familiar PRR P5, GG1, New Haven EP2, EP3, Milwaukee EP-3 and CUT/NYC P-motor design with two relatively small light motors diving each quill gear.  Pioneered in NYNH&H's 1911 experimental 069, it became one of the dominant designs prior to the development of Motor-Generator designs in the 1920s and rectifier designs in the 1950s.  AC and DC examples.

[/quote, above]

Of course the very conventional "wheel-barrow" axle-hung motor design should be addded.  First pioneered on Frank Spragues Ricihmond streetcar electrification, the axle-hung "wheelbarrow" arrangement pretty standard on diesels and most electric locmotives and nearly all commuter and high-platform subway/transit cars, not on low-floor light-rail and streetcarts.

A decent solution today because of the light weight of modern motors.