A handful of old GP38s and GP40s were recently rebuilt into two-unit road slug sets, and have been distributed on various GNWR system railroads in Canada.   SLR has four such sets, numbered 3803-3806 for the GP40M-3 mothers and 803-806 for the RM-1 slugs.  (Slugs are where one powered locomotive splits the electricity it generates between itself and an unpowered unit connected to it.)  The advantage of using slugs is that two slug pairs (two GP40M-3s and two RM-1s) will provide the same amount of tractive effort as four GP40s, while only requiring the use of two diesel engines.  Slugs are capable of low full-throttle speeds without wheelslip since the horsepower of a 4-axle GP40 is split between 8 axles, but that also means the running speed is lower compared to two GP40s.  As in the photo above, the GP40M-3s can be used as single units as well, which was the case while initial bugs were being worked out.

The units come from various backgrounds, but perhaps the most welcome additions are GP40M-3s 3805 and 3806, which are former GP40X units that had already run on the SLR in 2002 as SLR 3210 and 3209 (originally NS 7003 and 7000) respectively.  The histories of the other units are varied.  The slug GP40M-3s have more or less retained their original appearances while the RM-1s had most engine access doors and the whole radiator assembly replaced with blank sheet metal during rebuilding.

The GP40M-3s, when paired with slugs, are the loudest units I've heard on the line--probably because they're often in full throttle at low speed.  Because the two ex-GP40X's had their engines derated from 3500 hp to 3000 hp, they sound the same as the other GP40's.

Recorded January 03, 2007, 1 minute 34 seconds
22,050 Hz compressed, 645 KB 

RM-1 804, GP40M-3 3804, GP40 3002, GP40M-3 3806 and RM-1 806 have over 80 cars moving along at the foot of the Waterville, QC grade, on train 394.  Noteworthy in this recording is the excessive whine coming from one of the units (likely GP40 3002).  The whine seems to be from an imbalanced turbocharger rotor, which spins in excess of 16,000 rpm.  The whine was present nearly a month earlier, but it's likely only a matter of time before turbocharger repairs become necessary.

Recorded April 10, 2005, 1 minute 23 seconds
Re-transferred October 29, 2006
22,050 Hz compressed, 568 KB
44,100 Hz, 3,588 KB

Although standard practice for much of 2004 was to have GP40M-3's leading with RM-1's in the middle, subsequent locomotive mix-ups sometimes placed RM-1's on the point.  Such was the case with this train, where RM-1 805 leads GP40M-3 3806, RM-1 804 and GP40M-3 3804 on an 80-car freight headed up the 1% grade in Waterville, QC.  They were managing about 10 mph in run-8 but sped up to over 20 mph after the train crested the grade--a typical performance of the slug sets.  Wheelslip (and the resulting horsepower reduction) would prevent two GP40's from accomplishing the same feat.

The horn on 805 is the same as on all the RM-1's: a blasty Nathan K5LA.  As is evident in this recording, all chimes are fully functional!  The chorus of whines evident when the second unit passes is characteristic of 3804, which has a mixture of fans with 8 and 9 blades each.

Recorded June 06, 2005, 1 minute 3 seconds
Re-transferred October 29, 2006
22,050 Hz compressed, 429 KB
44,100 Hz, 2,712 KB

Talk about whining!  Seven locomotives--RM-1 805, GP40M-3 3805, RM-1 804, GP40M-3 3804, RM-1 806, GP40M-3 3806 and GP40 3206--hold back the 121 cars of a late-running Westbound 393 freight easing down the grade from Waterville, QC.  I'm not sure whether all the units were in dynamic brake mode, but I can safely say that GP40 3206 was!  In fact, 3206 in particular is the source of the peculiar fluctuating whining sound, caused by the dynamic brake fan spinning like there's no tomorrow while increasing and decreasing in speed.  The other locomotives produced a more subtle fan whine at a constant pitch.

Added bonus: the engineer greeted me with the horn.

Recorded Janary 29, 2004, 1 minute 3 seconds
Re-transferred October 29, 2006
22,050 Hz compressed, 431 KB
44,100 Hz, 2,722 KB

This was the first train I saw powered only by SLR slug sets.  The consist was GP40M-3 3803, RM-1s 805 and 804, and GP40M-3 (former GP40X) 3806 on a late-running 394.  The result was fairly impressive--two GP40M-3s, two 16-645 engines running, 65 cars, and a sustained speed of a little over 20 mph (32 km/h)... Not bad for a train usually requiring three GP40s!

The very long gap between the sound of the locomotives whining reveals the two near-silent RM-1s in the middle.  The horn of 3803 is a Nathan K5LA that had seen better days--a slightly squawking #5 bell and imperfect tuning rendered it not very melodious.  (It has since improved)

Recorded April 07, 2004, 1 minute 15 seconds
Re-transferred October 07, 2006
22,050 Hz compressed, 510 KB
44,100 Hz, 3,224 KB

This was the first time I witnessed SLR's road slugs battling the 1% grade entering Waterville, QC.  It was an impressive sight--the facts speak for themselves: 2 SLR slug pairs, 83 cars, full throttle, sanders blasting, 10 miles an hour.  Motive power was GP40M-3's 3803 and 3805, with RM-1's 805 and 806 between.

Recorded April 30, 2004, 44 seconds
Re-transferred October 07, 2006
22,050 Hz compressed, 260 KB
44,100 Hz, 1,914 KB

Not too often that a train is viewed from this angle!  Let's just say that I was trusting of the condition of the SLR tracks when I watched this train.  Here is SLR train 394 headed East with GP40M-3 3804, RM-1 804, GP40M-3 3806 and 62 cars.  The two Geeps, roaring and whining in run-8, were managing a little over 20 mph as they headed uphill.  The chorus of whines from 3804 is because of a mix-up of radiator fans with 8 and 9 blades (8 blades is normal). Shortly after passing, the engineer blew the pleasant K5LA of 3804 for the Courval road crossing North of Waterville, QC.

Short but sweet.  As 3804, 804, 3806 and GP40 3001 exit Waterville, QC, with train 394, the engineer blows a horn greeting, seeing me taking pictures.  The relatively short freight was an easy pull for the mid-throttle engines.

Recorded June 22, 2005,
Re-transferred October 29, 2006
22,050 Hz compressed, 431 KB
44,100 Hz, 2,722 KB

Another recording of the slug sets battling the 1% Waterville, QC grade.  This train had GP40M-3 3804, RM-1 804, GP40M-3 3805 and RM-1 805 in run-8, dragging 103 cars uphill at 10 mph.  This was one of the longest trains I've seen behind just two slug sets, a testament to their very strong pulling power at low speed.

Recorded May 09, 2004, 1 minute 44 seconds
Re-transferred October 07, 2006
22,050 Hz compressed, 712 KB
44,100 Hz, 4,501 KB

Yes, only two 16-645E3 engines were running on this train, but it could just have easily been four by the sound of them.  The roar is from GP40M-3s 3805 and 3803, with RM-1s 806 and 805 in between, slogging uphill towards Compton, QC, in full throttle at 15 mph (25 km/h).  This section of track North of Compton is a brief respite from the grade that stretches past the US border, and it allowed the units to get up to that speed.  By the time the last of the cars had passed and had started up a steeper section of track past Compton, the train's speed was down to a crawling 10 mph (15 km/h).  The engines were loud enough that I was ready to record the train for 15 minutes before it actually arrived; I first heard them as they battled up an earlier grade before Waterville, 3 miles (5 km) to the North.

The brassy Nathan P5 of 3805 was blowing for a rural farm crossing.  Note the whine that started up just as the engines were passing--it came from 3803 and is from one of the fans starting up.  I didn't count the cars on the train between taking pictures, but there were most likely more than 80.

A similar story here as the same lash-up--3805, 806, 805 and 3803--battled uphill at 10 mph into Waterville (QC) with 63 cars, heat waves above and hood doors rattling from the vibrations of full-throttle prime movers.  This is heard from a short distance North of the Waterville road crossing, just at the crest of the grade entering Waterville, and at this location the surrounding buildings and terrain create very impressive reverberations of the engine sounds. After the train had started to pass and head into flatter terrain, the slug units were able to bring the speed up to 20 mph or so.  A lack of any Intermodal cars (relatively lightweight) rendered this train proportionally heavier than some previous 394 freights.

Recorded February 06, 2004, 59 seconds
Re-transferred October 07, 2006
22,050 Hz compressed, 401 KB
44,100 Hz, 2,531 KB

Another horn greeting from an SLR engineer.  This train had GP40M-3 3806 leading RM-1s 804 and 805 and GP40M-3 3803.  The lead unit was at one point SLR GP40X 3209, and still has the Nathan P5 of former owner Norfolk Southern.  However, perhaps due to snow, bells 1 and 5 were silent, resulting in a sound that was actually more pleasant than that of the five fully functional chimes.  The two units maintained a decent speed (over 20 mph) with 57 cars on train 394.  The run-8 645 engines could be heard long before and long after the train had passed.

Here are 3806, 804, 806 and 3804 again on another 20 mph freight.  The sound of a jet at the beginning is quickly overpowered by the locomotives as they roar past with a 61-car Train 394.

Recorded March 14, 2005, 1 minute 58 seconds
Re-transferred October 07, 2006
22,050 Hz compressed, 809 KB
44,100 Hz, 5,115 KB

How slow was this train?  The gap between the first and second whistle blasts of GP40M-3 3806 was so long that the oscillating ditch lights on 3806 stopped flashing.

GP40M-3 3806 (with RM-1 805) and GP40 3206 passed the Waterville, QC crossing at about 10 mph, and were possibly in single-digit speed while climbing the 1% Waterville grade before the crossing.  However, after the train passed onto level track beyond Waterville, the speed was up over 20 mph.  The train was an afternoon 394 freight with 59 cars.