MU (Multiple Unit) OPERATION

This will be a somewhat simplified explanation of the items used for multiple control of Diesel Engines. Without a lengthy history or technical discussion lets look at what MU actually does and what is required. In it's simpliest terms MU is the operation of two or more diesels from a lead unit and under the control of the lead engineman. This has been accomplished by several methods: Electrically, Pnuematically, and radio signals. Several systems were tried and subsequentially discarded due to lack of compatibility. There was no governing body such as the A.A.R. since engines were not interchange equipment. The earliest reference I can find to a Federal Regulation about Multiple Unit Operation is in the I.C.C. Rules of Locomotive Inspection other than Steam. "When locomotive units are coupled in multiple control, all parts and componnents of each unit capable of providing power for propulsion or supplying the retarding effect which will enable the engineman to control the speed or stop the locomotive or train shall respond to control from the engineman's compartment of the controlling unit." Well so much for history! To MU there are several functions which must be controlled or monitored. Engine speed, therefore power output, is the primary item to be controlled. Other items requiring control/monitoring are the independent brake, sanders, steam generators, air compressors, electrical transition and forward/reverse control of the traction motors, and misc. alarms.
The electrical connections between units is a receptacle mounted at each end and connected by a flexible cable. Some are mounted on the walkway, some on stands. Refer to pictures to model your engine. The A.A.R. in the 60's recommended the use of a 27 pin system. Not all roads or manufacturers used this system. For the purpose of modeling, nearly all configurations looked the same when the cover was closed. EMD introduced the 16, 17 point receptacle which they used on the "E" and "FT" units. The 27 point jumper became their standard beginning with the "F3's" onward. Union Pacific used the 12 and 21 point type receptacles which are compatible with other 4 point throttles. All the above receptacles had the same 4 point control for throttles. Builders such as Baldwin, Westinghouse, Fairbanks-Morse and Lima used versions of Pnuematic (air) throttles. These units would not MU with other makes. Alco used a 3 point throttle control on their switchers and RS-1's. This will give a rough idea of what could be MU'ed together.
The air connection between units is by those hoses which hang down on the pilots and that one which emerges from under the frame and hangs down at about a 45 degree angle. This is the main trainline. All the air for the car brakes is supplied thru this line. Control for the brakes and sanders is thru the other lines. There are several types of brake/sander systems. The 24RL and 26RL are the most common and use 4 hoses per side. When the 24RL and 26RL have 3 hoses per side the sanders are controlled thru the MU receptacle. So, there is a simplifed explanation which with pictures should help your modeling from the late 40's to the present day.
So far we haven't mentioned the radio control system for MU'ing. Probably the most modeled system is the "Locotrol". This uses a radio signal from the lead engine to a slave control car. The slave control car has the electronics to receive, translate and transmit the lead engine commands via the conventional 27 pin receptacles and hoses to the following unmanned diesels. This allows starting with minimal slack, longer, heavier trains which do not exceed drawbar strength. Conventional MU signals are not as reliable when the number of powered units exceeds 8 units. I hope this will answer some questions and help with your modeling...hosam...For more details consult manufacturers operators manuals. These can be found at old booksellers and on on-line auctions.



07/24/01 I am detailing a P2K FEC GP7 as 613 in 1960(see cover photo of the Diesel Era FEC red and yellow issue). I have an idea for the canvas sunshades. I am going to attempt, to use model airplane tissue and dope like used to be applied to balsa models. I think you can shpe this with a few coats of dope(clear or canvas color) then use more to "firm" it up if in the extended position, wire could be used for the supports. I will let you know how this works, it may be a couple of weeks before I get to this. Let me know if anyone has attempted this before or if you have other suggestions. Bill Michael 07/24/01 Rather than dope, which being cellulose, is likely to do 'orrible things to your styrene cab, try using tissue brushed over with a mixture of scrap styrene dissolved in liquid cement. Go gently with it or it will have just as bad an effect as the dope! It was much favoured by the military vehicle modelling fraternity for canvas hoods on trucks etc, in the days when I did such things- early 'seventies technology still has some uses Aidrian Bridgeman 07/24/01 I use lead foil wrapped over a wire frame. Steve Orth 07/24/01 Better yet, acrylic paint, thinned appropriately. Jimmy Weierich 07/24/01 Being a UP modeler, this has come up before. UP used canvas sunshades until the 1970's. I agree with Steve Orth that his system of lead foil/wire frame works the best. Another way that I have used is to take A-Lines' PE shades, trim off the angled sides (leaving a rectangle of brass). After ACCing it to the cab, then I add a lower frame from wire. Together these make a strong assembly. I have taken several models around with our modular group and these sunshades have survived nicely. This works for fully extended shades. For a few of the shades, I roll the brass slightly to get a little "sag". For folded screens, I think that Steve Orth's method works the best. I paint the frame grey or silver and use Polly Scale "Earth" for the tan canvas. Gary Binder 07/25/01 I use wire for the frame and newsprint for the canvas. I also use newsprint for radiator covers. I like the color and the fact I don't have to paint it. All the ideas I've heard sound good. Steve Solombrino 07/24/01 Go out and buy yourself a nice bottle of wine. Get the good stuff with the lead foil wrapper on it. The lead foil is very thin and pliable and makes a great canvas sunshade. Bend some .012-.010 brass wire to create the frame and then just use a small amount of CA to attach the shade to the frame. Drill holes in the cab to fit the wire and to match your photos. Try Testors Model Master Military colors for paint. I like the the Khaki for newer sunshades and Field Drab for older looking shades. I put a picture of the IC GP-40 that I used the lead foil on in the group's file section. Also if you would like a little better close up of it try taking a peek here: IC GP-40. You can model them easily rolled up or extended. I brush paint them to give a rougher surface. With the lead foil you just cut it with a scissors, bend it the way you want it and glue into place. I prefer it to using tissue since it's faster. Also, the wine will come in handy with the wife/girlfriend after spending all day in the hobby room with your trains. Happy modeling, Brian Strom 07/25/01 I've built them from very thin brass sheet(can't remember the thickness number but use the thinnest possible maybe .002 or .001 for HO scale).build the support frame from Detail Associates brass wire about .008 or .010(solder frame to brass "canvass"),leave the frame ends long then drill holes into the body to secure inside(bend over the ends and CA inside for plastic shells).The thin brass sheet will be more to scale thickness and looks more like canvas than is possible with tissue. Dave ??



Classification Lights are found on front of the motive power be it Steam or Diesel. Markers are found on the rear of Steam Engine tenders and the Caboose, at least till Cabooses were eliminated. Classification lights on Steam Locomotives were generally the same as those on Cabooses. Generally cylindrical in shape with 3 green lenses and one red lenses. Early lights used whale oil, kerosene and finally electricity for illumination. Generally most roads had all three green lenses showing when the train was moving. If the train took a siding the red lenses was rotated to show to the rear, with a green lenses to front and rear. Some roads used a yellow lenses for one of the green and showed the red to rear and yellow to the side. The markers on the caboose were displayed the same as the locomotive.



Check this web site Airhorns for pictures and sounds of various horns. The following horns are available from various hobby shops for use on Diesels:
Nathan KS1 Cal-Scale 422 1 chime
Nathan KS2 Cal-Scale 423 1 chime
Nathan K2 Cal-Scale 424 1 chime fwd, 1 chime rear
Nathan K3 Cal-Scale 425 1 chime fwd, 2 chimes rear
Nathan K4 Cal-Scale 426  
Nathan K5 Cal-Scale 427 3 chimes fwd, 2 chimes rear
Nathan P3 Cal-Scale 420 2 chimes fwd, 1 chime rear
Nathan P5 Cal-Scale 421 3 chimes fwd, 2 chimes rear
Nathan M3 Cal-Scale 428 2 chimes fwd, 1 chime rear
Nathan M5 Cal-Scale 429 3 chimes fwd, 2 chimes rear
Leslie S25 Custom Finishing 120 1 chime
EMD   Custom Finishing 215 1 chime
Leslie A200 Custom Finishing 219 1 chime
Leslie S2B Custom Finishing 220 1 chime fwd, 1 chime rear
Leslie S3 Custom Finishing 221 2 chimes fwd, 1 chime rear
Leslie S3L Custom Finishing 222 3 chimes fwd
Leslie S3L Custom Finishing 223 3 chimes fwd
Leslie S3L Custom Finishing 224 3 chimes fwd
Leslie S5T Custom Finishing 225 5 chimes fwd
Alco FA/PA Details Associates 1605 1 chime
Alco RS Details Associates 1606 1 chime
Leslie A200 Details Associates 1608 1 chime
Nathan P3/P5 Details Associates 1601 can be assembled to match
Nathan M3 Details Associates 1602 can be assembled to match
Nathan M5 Details Associates 1603 can be assembled to match
Hancock Air Chime Details Associates 1604 1 chime
Wabco A2 Details West 173 1 chime short bell/long bell
Wabco E2 Details West 174 1 chime
Leslie S3L Details West 190 2 chimes fwd, 1 chime rear
Leslie S5T Details West 191 3 chimes fwd, 2 chimes rear
Nathan P3 Details West 175 2 chimes fwd, 1 chime rear
Nathan M3 Details West 186 2 chimes fwd, 1 chime rear
Nathan M5 Details West 187 3 chimes fwd, 2 chimes rear
Leslie S5T Utah Pacific 60 3 chimes fwd, 2 chimes rear



04/05/01 I'm not 100% sure what type of beacon that you wan't to model, but it is possible (quite easy actually) with DCC. I'm not sure if Lenz decoders offer the options for this, but the nice thing about DCC and NMRA standards throughout the industry is that you can use another manufacturers decoders with your Lenz systen or vice versa. I know for sure that some of the Digitrax decoders have the beacon option that you need and I think the Soundtraxx decoders do as well. Here's what I do for beacons on my Digitrax equipped Milwaukee diesels. I take a Details West rotary beacon (#235-106 at Walthers) and glue (ACC) the beacon to the metal base, then cut off the little orange "stem" coming from the beacon through the metal base. I then very carefully drill a hole (this should be no problem for those of you who drill out Kato handrail stantions) from the base up through the orange plastic piece being careful to stop before the bit comes out through the top :-) Then I take a Circuitron 1.40mm 3v light bulb (#800-741802 at Walthers) and insert it into the hole that I just drilled and fasten it into place in the beacon with Micro Kristal Klear. Using Kristal Klear allows you to easily remove and replace the bulb should it ever fail. Next, drill the hole in the roof of your diesel (just big enough for you light bulb wires) and install the beacon assembly, again secure it with the Kristal Klear. Now all you have to do is hook the bulb wires to the proper place on the decoder, of course you need to use a resistor (800-941812 at Walthers). Then just program your decoder to make the bulb do what you want (rotating beacon, flashing beacon, strobe, etc). I use the rotating beacon effect and it is awesome. You even have the option to speed up or slow down the flash rate ! I have just scratched the surface with the possibilities of DCC lighting, but needless to say, DCC is the ultimate in prototype modeling :-) Keith Fink



The following is from Code of Federal Regulations (CFR) Title 49, chapter II, part 229, sec. 229.125. d) Effective December 31, 1997, each lead locomotive operated at a speed greater than 20 miles per hour over one or more public highway- rail crossings shall be equipped with operative auxiliary lights, in addition to the headlight required by paragraph (a) or (b) of this section. A locomotive equipped on March 6, 1996 with auxiliary lights in conformance with Sec. 229.133 shall be deemed to conform to this section until March 6, 2000. All locomotives in compliance with Sec. 229.133(c) shall be deemed to conform to this section. Auxiliary lights shall be composed as follows: (1) Two white auxiliary lights shall be placed at the front of the locomotive to form a triangle with the headlight. (i) The auxiliary lights shall be at least 36 inches above the top of the rail, except on MU locomotives and control cab locomotives where such placement would compromise the integrity of the car body or be otherwise impractical. Auxiliary lights on such MU locomotives and control cab locomotives shall be at least 24 inches above the top of the rail. (ii) The auxiliary lights shall be spaced at least 36 inches apart if the vertical distance from the headlight to the horizontal axis of the auxiliary lights is 60 inches or more. (iii) The auxiliary lights shall be spaced at least 60 inches apart if the vertical distance from the headlight to the horizontal axis of the auxiliary lights is less than 60 inches. (2) Each auxiliary light shall produce at least 200,000 candela. (3) The auxiliary lights shall be focused horizontally within 15 degrees of the longitudinal centerline of the locomotive. (e) Auxiliary lights required by paragraph (d) of this section may be arranged (1) to burn steadily or (2) flash on approach to a crossing. If the auxiliary lights are arranged to flash; (i) they shall flash alternately at a rate of at least 40 flashes per minute and at most 180 flashes per minute, (ii) the railroad's operating rules shall set a standard procedure for use of flashing lights at public highway-rail grade crossings, and (iii) the flashing feature may be activated automatically, but shall be capable of manual activation and deactivation by the locomotive engineer. [[Page 306]] (f) Auxiliary lights required by paragraph (d) of this section shall be continuously illuminated immediately prior to and during movement of the locomotive, except as provided by railroad operating rules, timetable or special instructions, unless such exception is disapproved by FRA. A railroad may except use of auxiliary lights at a specific public highway-rail grade crossing by designating that exception in the railroad's operating rules, timetable, or a special order. Any exception from use of auxiliary lights at a specific public grade crossing can be disapproved for a stated cause by FRA's Associate Administrator for Safety or any one of FRA's Regional Administrators, after investigation by FRA and opportunity for response from the railroad. (g) Movement of locomotives with defective auxiliary lights. (1) A lead locomotive with only one failed auxiliary light must be repaired or switched to a trailing position before departure from the place where an initial terminal inspection is required for that train. Greg Ockander


S.A. McCall