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  • MLW M-636 dimensions and details

  • Discussion of products from the American Locomotive Company. A web site with current Alco 251 information can be found here: Fairbanks-Morse/Alco 251.
Discussion of products from the American Locomotive Company. A web site with current Alco 251 information can be found here: Fairbanks-Morse/Alco 251.

Moderator: Alcoman

 #1187108  by trainiac
 
I took a bunch of measurements of CP M-636 #4723 on static display in Farnham, QC in March to make drawings of MLW M-liners. The unit is now a rusted hulk, with many missing parts - it's even partly slipped off its rubber suspension pads at one end - but it's still intact enough to accurately measure.

Here are the drawings I made based on the measurements:
http://trainiax.net/mescaleloco-results ... &scale18=1

And here are the measurements I took from 4723 (except the cab roof height, which I interpolated from photos):
Left side: http://trainiax.net/drawings/18-mlw/m6/ ... cp-2-m.GIF
Right side: http://trainiax.net/drawings/18-mlw/m6/ ... cp-2-m.GIF

Most of the dimensions are shared among all M-630 and M-636 variations. Many of the cab and hood dimensions and some of the underframe dimensions are also shared with the ALCO C-636.

I've also taken a whole bunch of detail photos of 4723 (in 2008 and this past March) which I've uploaded as well:
http://trainiax.net/mephotosearchresult ... erpage=100
 #1187569  by Allen Hazen
 
Thank you, Trainiac! Thosedimensions will beinvaluable to anyone trying to make a detailed and accurate model.

Did you, b.t.w., get a figure for the height of the deck above the railhead? Alco used two different trucks (the drop-equalizer Trimount and the "Hi-Ad") on its six-axle Centuries, and there is a noticeable difference in deck height between C-630 (*) with the two truck types-- it would be interesting to know how the "Dofasco" truck used by MLW compares in this regard.

(*) All C-628 had Trimount and all C-636 had Hi-Ad, so the C-630 was the only model produced with both... with all three, actually, if you count the "Dofasco" equipped C-630Mand M-630 as belonging to the same model as US-built C-630!
 #1187640  by trainiac
 
I didn't measure the deck height because the wavy rails the unit sat on, worn wheels, damaged front secondary suspension and (likely) reduced weight from removed components all might have affected the height. I seem to recall finding a listed dimension of 72" somewhere for the ALCO C-636 (which is the same height) but I can't remember where. My previous photo estimates for the deck height of the C-636 (which I drew in a smaller scale 3 years ago) averaged to 71.5".

After settling on a figure somewhere around 72", I tried calculating the deck height indirectly based on the measures I had for frame thickness minus the bottom plate (17.75") and truck-to-frame height (6.25" - at the rear, with intact secondary suspension), along with photo estimates from several units of the dimension between the axle center and top of the truck (which averaged to 27.75"). Adding 20" for the wheel radius (axle-to-rail) gives a total deck height of 71.75", which is what I used in the drawing. I've updated the drawing with the deck height listed.

The height of the C-630M and M-630/M-636 is indeed different. The references I've found have all listed the deck height as 69" for Century road units except the C-636. I've used a deck height of 69" for my older ALCO Century drawings, and a CP paint diagram I found lists the deck height of the MLW C-630M as 69.25". The C-630M lacks the large spacers above the secondary suspension found on the M-liners.
 #1187734  by trainiac
 
Thanks Tom! I hope to have more ALCOs drawn in the future, including models I haven't drawn before. Ideally, I'd like to get more measurements from preserved units, including from the incredible collection of MLW units at Exporail.
 #1187753  by trainiac
 
Allen - I had forgotten about the C-630s with Hi-Ads! My old drawings have them at the same height as the Tri-mount equipped units, but in looking at photos it's obvious the Hi-Ad units ride higher. They also use the coupler pocket design of the C-636 and M-liners, so I would assume they ride at the same height.
 #1187764  by mandealco
 
Your plans are a valuable resource for modellers. I use them regularly, and have built several N-scale Alcos and MLWs with help from your plans. Thanks for your efforts.
Cheers
Steve
 #1188085  by Allen Hazen
 
Trainiac--
Thanks for reply! I had wondered whether the damage to the secondary suspension of the unit you measured had led you to think measuring its deck height would be pointless...

I wish I had more to contribute to the discussion. I can report on a couple of printed sources.

(1) "Railroad Model Craftsman" ran a series of articles on Alco "Century" models in 1984-1985: articles every other month starting with the C628 in June 1984, C630 in August, Hi-nos C628 and C630 in October, C636 in January 1985, four-axle types later in 1985. The articles include HO scale drawings and text by "Win Cuisinier" (pen name of Preston Cook), so I trust their scholarship and research MUCH more than the average article in railfan or model railroading magazines. Anyway... The August 1984 article has drawings of C630 with Trimount and Hi-Ad trucks: given the small scale of the drawings, I haven't tried to measure the deck heights in them, but the deck is noticeably (in the 1 to 2 millimetre range) higher in the drawing of the Hi-Ad equipped unit. The caption notes that the horns -- often mounted on the centerline of the cab roof on Trimount-equipped units -- were, for clearance reasons "normally" mounted to one side, over the engineer's position. There is also a photograph of Reading 5301 (Trimount trucks) and 5307 (Hi-Ad) coupled together, showing a marked difference in deck height.

(2) "Mainline Modeler" had C630 articles in its August and September 1989 issues: August has drawings of the M630 and a Trimount equipped C630 (sources not given-- the M630 has numbers on it suggesting it was originally a "general arrangement" drawing with an accompanying list of parts, perhaps from an MLW advertisement, and the C630 looks as if it might have been a diagram for how topaint the Reading units), and the September article has S-scale drawings (front, back, both sides, top view) by Robert L. Hundman. No measurements for deck height given, BUT:
-----> I assume the superstructure height above the deck (i.e. height of cab and hoods) was the same in all versions, and height over the cab roof IS given: 14' 10" for the version with Trimounts, 14' 10.5" with Fairbanks-Morse trucks (five units for Norfolk andWestern were built with trucks from FM Train Master units), 15' 1.3125" with the "New Truck" (= the truck used on Canadian C630M and M630 units), and 15' 3" with the Hi-Ad truck.
 #1188087  by Allen Hazen
 
Consilience (to use a word from Philosophy of Science jargon) is good: if two different lines of evidence and reasoning lead to the same answer, it properly increases our confidence. Your dimensioned drawing gives 109 inches as the height of the cab (deck to rooftop). Add that to the 69 inch deck height you quote for "conventional" Alco C628 and C630 and we get 178", which is 14' 10": the figure given for total height over cab roofs for these units in "Mainline Modeler."
 #1193314  by trainiac
 
Just out of curiosity, I tried re-measuring the deck height of the ALCO C-636 based on a fantastic telephoto detail photo - perfect for measuring (the 14th photo at http://dieseldetailer.proboards.com/thr ... ail-photos). The unit was DL 3642, in service with new-ish wheels, and I compared the deck height to the #5-6 axle spacing (79.375 inches). The measurements for deck-to-axle and deck-to-rail suggest a deck height of between 71.75 and 72.10 inches - so to be ridiculously nit-picky, I'm probably 0.25" short in my drawing (1 pixel).

I've noticed that the overall height and the cab roof height are sometimes mixed up - one such error in a railroad diagram resulted in all my previous Century drawings being 2 inches too tall. One thing that may affect overall height listings between the ALCO and MLW versions is that on the C-636, the central air intake is notably higher than both the cab roof and the radiator walkway - about 15' 3" by my photo measurements. This is not the case on the M-636 as-built, which has a lower central air intake. The exhaust stack and the raised sections over the radiators and central hood are the highest points on the late M-liners (the radiator section is 15' 1.5" in my drawing).
 #1240657  by trainiac
 
I have just completed drawings of the MLW C-424 based on a similar series of measurements I took from CP #4237 at Exporail. I didn't climb the walkway, so my measurements were from the ground only, but they still gave me a lot to work from.

CP modified their C-424 units with (among other things) a rebuilt battery box area with hinged covers, which necessitated moving the 4th rearmost handrail stanchion rearward. The battery box dimensions are not the same as when the units were built, and they vary slightly from one unit to the next. Also, CP #1100 (a C-424 control cab also at Exporail) showed some minor detail and dimension variations compared to #4237 and other C-424 units, which I'm guessing is because it's a major wreck rebuild (originally #4236).

Here are the drawings I've made so far based on these dimensions
http://trainiax.net/mescaleloco-results ... N&lrtype=L" onclick="window.open(this.href);return false;

And here are the dimensions
http://trainiax.net/drawings/18-mlw/c4/ ... cp-4-m.GIF" onclick="window.open(this.href);return false;
http://trainiax.net/drawings/18-mlw/c4/ ... cp-4-m.GIF" onclick="window.open(this.href);return false;
 #1240812  by mandealco
 
Another great job on the drawings, extremely useful, and very much appreciated by myself and no doubt many others.

Just some further modifications to CPR's C-424's that are worthy of mention. In later years, a number of C-424's received alternators from retired M-630 and possibly M-636s. These can be distinguished by a couple of external changes. As alternator equipped Alcos used an air start system, modified C-424s received a third air tank, added to the LHS. They also had a small curved bulge added on the top of the central air intake area. Three of the modified units have been on the M&E. Former ERS 4204 (still at Morristown) and 4223 & 4228, now both on the WNY&P. The third air tank is the easiest give away. Other units on the M&E retained their main generators: 4216, 4231 and 4240.

Someone may have more info on this, and can identify all alternator equipped units.

Cheers
Steve