Snails on the highway? CNW seems to have had quite a few "road slugs". They seem to have been made out of old RS3s. What is the difference between a road slug, and a B unit?
Thanks to Chris / CopCarSS for my avatar.
The "Road Slug" has no prime mover, no main generator; only traction motors which are fed from the prime mover and main generator of the "mother unit"
The "B Unit" has its own prime mover and main generator that feed its traction motors. However, it lacks a control stand and must be controlled from a lead unit via MU cables.
Mike
A minor correction. The B unit will often have hostler controls so it can be moved independently. Obviously it won't have the full range of controls and gauges that are found in a locomotive with an actual cab.
One reason for higher horsepower in locomotives is to allow faster running speeds and acceleration on fast freights. This higher horsepower is essentially wasted on a slow drag, when it provides more power than the traction motors can safely handle. Hence the slug, so that power can be split among more traction motors. In effect you get two 1000hp locomotives running from a single 2000hp prime mover. Speed will not be as good, but the pair will be able to pull far more tonnage than the original single locomotive. And the slug is a lot simpler and thus cheaper than a second locomotive.
John
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
oltmanndCSX's road slugs are particularly well done. They filled a current need for branch line power to replace older Geeps using GP40-2s that were surplussed from road service by newer power and GP30s and GP35s that were otherwise obsolete. They wired the GP40-2s as mothers and rebuilt the GP30/35s as road slugs. They retained the fuel tanks and installed a transfer pump so the mother could run for weeks without refueling. They installed field shunts on the slug so that it could be cut out on the fly and allow the pair to operate at higher speeds. The cab and controls on the road slug allowed the pair to operate easily in either direction w/o turning. The cost to modify the mother and rebuild the road slug were quite a bit cheaper than purchasing a couple of GP15s and provided the same performance with fewer moving parts.
I have only seen a few "slug sets", in actual service; Union Pacific seemed to get them through Parson, Ks. on some trains, on an irregular basis . Most of those trains had a UP unit on the lead. So they wold seem to work well when they go" off the Reservation" and are assigned to service on other railroads trains.
I would guess if they were problematic for operation, the receiving railroad would refuse to accept them?
I wonder if with theloss of the weight of the units prime mover and alternator, do these units get extra ballasting on the rebuild, to assist in maintaining a predictable level of traction?
In a previous thread on the CSX's version of the GE product, that became the CW44AH and was ballasted approx 40,000 # heavier for work in the mountais with drag freight; are the mother and slug sets restricted to the flatter terrain of the railroad?
It seems to me, that if this is a successful method of gaining more tractive effort, fairly cheaply. Other railroads would also be using this type of power for road applications. I have seen slug sets on Santa Fe, and Frisco, or +Bn+BNSF; used in yard, local, hump applications. Not specific to road locomotive power applications. Is this because they are a 'niche' use type of unit?
samfp1943 oltmanndCSX's road slugs are particularly well done. They filled a current need for branch line power to replace older Geeps using GP40-2s that were surplussed from road service by newer power and GP30s and GP35s that were otherwise obsolete. They wired the GP40-2s as mothers and rebuilt the GP30/35s as road slugs. They retained the fuel tanks and installed a transfer pump so the mother could run for weeks without refueling. They installed field shunts on the slug so that it could be cut out on the fly and allow the pair to operate at higher speeds. The cab and controls on the road slug allowed the pair to operate easily in either direction w/o turning. The cost to modify the mother and rebuild the road slug were quite a bit cheaper than purchasing a couple of GP15s and provided the same performance with fewer moving parts. I have only seen a few "slug sets", in actual service; Union Pacific seemed to get them through Parson, Ks. on some trains, on an irregular basis . Most of those trains had a UP unit on the lead. So they wold seem to work well when they go" off the Reservation" and are assigned to service on other railroads trains. I would guess if they were problematic for operation, the receiving railroad would refuse to accept them? I wonder if with theloss of the weight of the units prime mover and alternator, do these units get extra ballasting on the rebuild, to assist in maintaining a predictable level of traction? In a previous thread on the CSX's version of the GE product, that became the CW44AH and was ballasted approx 40,000 # heavier for work in the mountais with drag freight; are the mother and slug sets restricted to the flatter terrain of the railroad? It seems to me, that if this is a successful method of gaining more tractive effort, fairly cheaply. Other railroads would also be using this type of power for road applications. I have seen slug sets on Santa Fe, and Frisco, or +Bn+BNSF; used in yard, local, hump applications. Not specific to road locomotive power applications. Is this because they are a 'niche' use type of unit?
According to one of the Kalmbach Diesel Spotter's guides I own, at least the first batch of CSX road slugs built actually had concrete blocks installed in place of the engine for ballast...Other railroads have used road slugs, IINM both CP and NS operate some..CSX predecessor RR SCL actually bought new built road slugs from GE back in the 70's which were built using U36B components and were mated to U36B mother units..
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Murphy Siding Snails on the highway? CNW seems to have had quite a few "road slugs". They seem to have been made out of old RS3s. What is the difference between a road slug, and a B unit?
I believe C&NW also had road slugs made out of old F b-units...they'd use them between sets of GP35's.
carnej1According to one of the Kalmbach Diesel Spotter's guides I own, at least the first batch of CSX road slugs built actually had concrete blocks installed in place of the engine for ballast.
oltmanndA B unit never attacked your tomato plants.
That could depend upon where you set them out.
Johnny
DeggestyoltmanndA B unit never attacked your tomato plants. That could depend upon where you set them out. Johnny
MILW205 Murphy Siding Snails on the highway? CNW seems to have had quite a few "road slugs". They seem to have been made out of old RS3s. What is the difference between a road slug, and a B unit? I believe C&NW also had road slugs made out of old F b-units...they'd use them between sets of GP35's.
Here's a link for the background of the C&NW road slugs: http://utahrails.net/cnw/cnw11.php#bu-28 Scroll down to the bottom for all C&NW slugs.
While CSX's road slugs originally did have fuel tanks and transfer pumps, they have since been removed. So the only fuel is now carried on the mother. And for some reason, the heaters never quite work right on the slugs.
Nick
Take a Ride on the Reading with the: Reading Company Technical & Historical Society http://www.readingrailroad.org/
Our community is FREE to join. To participate you must either login or register for an account.