simon
Probationary Member
Posts: 12 
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Post by simon on Mar 21, 2016 11:59:30 GMT -5
When I visited Florida in 1990, I photographed what I was told was a Slug unit. Having had all my photo's and other railroad I bought whilst out there including 5 ho loco's stollen in a robbery I have no details such as unit numbers. The unit looked to me like a loco that had been reduced in hight by about 50% so I pressume it had no engine and radiators, so was it used as extra break power or where the traction motors drive by the lead loco?
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Post by tjmfishing on Mar 21, 2016 12:44:20 GMT -5
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Post by iomalley on Mar 21, 2016 12:50:17 GMT -5
You are correct. It could have been a slug, or a more rare braking sled. Either of which look like a vertically-challenged locomotive.
With slugs, there is a 'mother' semi-permanently coupled to it to share the excess amperage generated by the locomotive's generator (or alternator) in the first transition. (kind of like a 1st gear so to speak) as the loco increases speed, the 2nd and subsequent transitions (aka gears) change the output from "high amperage, low speed" to "low amperage, high speed"
The excess amperage is generally waste energy on most locomotives when starting to pull, so with a slug attached, the excess power is sent (via cables) to a slug to turn that electricity into pulling power. Once the loco and slug make 2nd transition, the power being sent to the slug drops off and she does little work after that until the unit slows down again or stops.
Slugs are predominately used in yard work (CN, NS, UP, CP etc), but some railroads (MILW, KCS for example) use road slugs to nudge a train into motion to overcome the starting energy required to move it. Slugs have very few internal components. They have wiring (obviously) and blower fans that cool the traction motors on the trucks, and some road slugs have dynamic brakes and cabs with full crew controls in them. (CSX, NS etc)
Braking sleds are usually only found in larger yard assignments (SP used them) where yard engines handle long cuts of cars without the airbrake system charged up. These are usually retired units that are lopped down in height, with as much ballast weight as necessary added to help the yard engine(s) stop the cut of cars.
Slugs and sleds are usually home-built creations, by their respective owners. There have been some purchased new that way (CN's HBU4s come to mind) but the lions share are usually former, retired locomotives that have lost their identity (and guts) as locomotives.
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Post by jmlaboda on Mar 21, 2016 17:24:29 GMT -5
While that is true about yard slugs road slugs are capable of providing additional traction up to around 45 m.p.h. depending on their design.
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Post by iomalley on Mar 21, 2016 18:04:38 GMT -5
I remember hearing that GEXR, in the early years, was using this road slug set to haul a string of salt cars and plow snow through 'mustard cut' at the same time. Its no wonder this set didn't last...  Its a cool consist though. |
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simon
Probationary Member
Posts: 12
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Post by simon on Mar 22, 2016 11:16:27 GMT -5
thank tou for all the infomation every one. I just wish that the low life who robbed us suffered (if you see what I mean) it would have been so much easier with the photo's, about 300 or so, as I'm tempted to make one as a reminder of what for a visitor from the UK is unusual.
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brian
Road Foreman
Posts: 62
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Post by brian on Mar 23, 2016 7:57:20 GMT -5
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simon
Probationary Member
Posts: 12
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Post by simon on Mar 23, 2016 8:02:53 GMT -5
yes that looks just like the one I saw around Tampa. Were any converted from other loco's? If so I pressume that they would be built on available older locomotives? And thanks for the photo by the way, brings back happy memories.
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Post by jmlaboda on Mar 23, 2016 14:46:15 GMT -5
No. The GE "Mates" were build new on new underframes much like other GE 4-axle products of that time. These were some of the earliest "Road Slugs" that could achieve the higher speed (45 m.p.h.) before they would cut out, allowing for a train with such units to reach a bit higher speed with greater tractive efforts compared to the "parent" locomotives alone could achieve.
Also, the cabbed Road Slugs in use on CSX were CSX creations... never done while the lines were Seaboard Coast Line/Seaboard System RR.
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Post by iomalley on Mar 24, 2016 10:45:54 GMT -5
Oh I forgot to add, there are also RCL sleds. These are ex locomotives that house radio control (beltpak) gear in them, and usually (as in the case of these UPYs) nothing more. If you plugged a regular non-remote controlled loco into this unit, you can convert the consist into a remote controlled consist.  CP and BCR used old B units for robot cars which are just radio receivers that transmit control to locomotives located elsewhere in the train. Sometimes they house air compressors in them as well to help with the volume of air.  We could delve even deeper into air repeater cars but I'll stop now.  |
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simon
Probationary Member
Posts: 12
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Post by simon on Mar 24, 2016 13:38:12 GMT -5
yep Sean, it's becoming a subject I could become very intrested in to a point of it becoming the only thing I will model! As before thanks to every oned for the info.
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