FYI: The FL9 was not originally designed for the New Haven and Park Ave. viaduct. The FL9 was an EMD solution to the problem of not having enough water on board for steam heat on long distance passenger trains that normally used F-units. They took the FP9, stretched it, and added water tanks both fore and aft of the prime mover. As the total water capacity was then quite large, they added the 5th axle to deal with the weight. They never sold.
Meanwhile, the New Haven came knocking, looking for a dual-mode loco. Since cost is always a concern (especially for the NH), EMD took the unused FL9 design, removed the new water tanks and added 3rd rail gear. The NH orded 30 of them (orignally they wanted 88). The first two had Blomberg front trucks. These were found to be unsuitable, so they were switched out for B-Flexicoils. A few years later in 1960, the NH desperately needed more passenger locos, and applied to the Gov't for a loan for more units (as EMD would not accept the NH's credit). The Gov't agreed, but only if 1) the units were of existing design, and 2) they were to be used in passenger service only. Only, EMD had started making GP18's by then, so EMD cranked out 30 of what should be called FL18's (567D, 1800Hp)...but they called them FL9's for the Gov't's agreement. Also, they removed nose MU and the 3rd seat in the cab for the brakie (the NH didn't really care, they just stuck an older unit between two new ones).
It is interesting to wonder what would have happened if EMD had not had the FL9 "water buffalo" design in the books. Would an 4-axle FL9 w/ 3rd rail gear be within the axle loadings of Park Ave.?
Paul A. Cutler III************Weather Or No Go New Haven************
oltmannd wrote: CNW 6000 wrote: beaulieu wrote: jrw249 wrote:So E units don't have 3 traction motors per truck?No, just two motors. If they had three it would be a C-C locomotive. Letters indicate powered axles, numbers indicate unpowered. Would having a C-C arrangement have helped these units run longer/better?There is no room in the A-1-A truck for a 3rd motor. You'd have to go to the Flexicoil truck and 40" wheels. (E's have 36" wheels) Flexicoils aren't exactly a high speed design....
CNW 6000 wrote: beaulieu wrote: jrw249 wrote:So E units don't have 3 traction motors per truck?No, just two motors. If they had three it would be a C-C locomotive. Letters indicate powered axles, numbers indicate unpowered. Would having a C-C arrangement have helped these units run longer/better?
beaulieu wrote: jrw249 wrote:So E units don't have 3 traction motors per truck?No, just two motors. If they had three it would be a C-C locomotive. Letters indicate powered axles, numbers indicate unpowered.
jrw249 wrote:So E units don't have 3 traction motors per truck?
No, just two motors. If they had three it would be a C-C locomotive. Letters indicate powered axles, numbers indicate unpowered.
Would having a C-C arrangement have helped these units run longer/better?
There is no room in the A-1-A truck for a 3rd motor. You'd have to go to the Flexicoil truck and 40" wheels. (E's have 36" wheels) Flexicoils aren't exactly a high speed design....
With the long vertical suspension travel and a little more lateral added to the secondary suspension along with a good damping package, the SD Flexicoil would be the best choice if there was really a need for a 3 motor, 3 axle truck in passenger service. Certainly a much better choice than the HTC truck EMD put under the SDP40F's. But today, any pedestal truck in passenger service creates a lot of wheel and truck maintenance to maintain stability. And with AC traction, 2 motors per truck are sufficient if you want to go fast.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Dan
I'm sure part of it is that Amtrak needs engines that will work everywhere in the U.S., not just in one specific region.
When E-units were being made, the individual railroads were the ones buying them, so a flat-land railroad (like the Burlington) would buy E-units for high-speed passenger service, whereas a line that went thru mountainous territory (GN,NP) would choose F-units. The F's worked fine on flat prairie lines too, but the E-units had trouble in the mountains, so the F's with two axle trucks were more versatile.
oltmannd wrote: jrw249 wrote:Do the E units have two diesel engines and generators?Yes. One powers the front truck and the other the rear truck.
jrw249 wrote:Do the E units have two diesel engines and generators?
Yes. One powers the front truck and the other the rear truck.
FYI: the Metra E units had 3 motors inside: the two mentioned above, and the third for coach power. The motors were Cummins for many years, which were replaced by Detroit engines.
wyomingrailfan wrote:I believe the idler was used to make the E units have a better ride.
The ride on an E8/9 was the best I ever had (on a train). So smooth, and so slippery!
oltmannd wrote: YoHo1975 wrote:Why are bloombergs so popular still? Why didn't the HT-B truck on the GP40X become wide spread? I mean, I realize that the HT-B didn't take off and therefore there are approximately a bazillion Bloomberg B and M trucks to scavange, but still. If they were such a nightmare....I know very little about the HT-B. That'd be a good one for bogie_engr. Hope he chimes in. The Blomberg is a proven design with good ride characteristics (with the leaf spring secondaries, anyway), and it's easy to do brake shoes and adjust piston travel, but no one would start from scratch today and come up with that design. As long as there are good frame castings floating around, the Blomberg will soldier on. Big steel castings are expensive.
YoHo1975 wrote:Why are bloombergs so popular still? Why didn't the HT-B truck on the GP40X become wide spread? I mean, I realize that the HT-B didn't take off and therefore there are approximately a bazillion Bloomberg B and M trucks to scavange, but still. If they were such a nightmare....
I know very little about the HT-B. That'd be a good one for bogie_engr. Hope he chimes in. The Blomberg is a proven design with good ride characteristics (with the leaf spring secondaries, anyway), and it's easy to do brake shoes and adjust piston travel, but no one would start from scratch today and come up with that design. As long as there are good frame castings floating around, the Blomberg will soldier on. Big steel castings are expensive.
The HT-B story probably belongs in a different thread but here goes:
The GP swinghanger truck, as EMD calls it, is still around because there was no incentive to design a new 2-axle truck once the HT-B died it's quick death. The HT-B was created simply to improve the weight shift between axles that the GP swinghanger truck suffers from so badly. When a locomotive equipped with GP trucks is working at 25% adhesion, the lightest axle (which ever axle is leading on the lead truck) is at about 84% of it's static axle load while the trailing axle of the trailing truck is at about 116% of static. Before the introduction of the Super Series wheel creep control, this caused the adhesion capability of the locomotive to be limited by the slip of whichever wheel slipped first, almost always the lead wheel of the lead truck due to the weight shift. The HT-B was designed to address that with its inclined rubber secondary suspension focused at rail height and the much lower centerbearing. The net result was almost no weight shift between axles within one truck and only the weight shift between trucks due to the coupler height above the rail. So at the same 25% adhesion, the HT-B lead truck axles are at about 96% of their static weight and the trail truck axles at about 104%. The HT-B was a technical success but being introduced with half of the GP40X prototypes, the other half with GP swinghanger trucks, allowed head-to-head adhesion testing to demonstrate the benefit of the lower weight shift. All GP40X's had Super Series wheel creep control systems and the result of testing showed no significant overall locomotive adhesion improvement with the HT-B truck. It was theorized that the creeping lead axle of the GP swinghanger truck provided a beneficial cleaning effect on the rails. Regardless, the main reason to introduce the new truck was proven no advantage. The many disadvantages of the HT-B included high production cost, a different underframe design due to the low mounted centerplate, stiffer ride compared to the leaf spring GP's, and a longer wheelbase that cut into the limited space on a GP model for fuel. But I think most importantly, EMD at the time did a good business in LRO (Locomotive Rebuild Order) orders where a customer would trade-in a unit for re-use of trucks, traction motor frames and some engine parts. Without trade-in credit for the trucks, the value of the trade-in was minimal so EMD lost a major competitive marketing advantage. So before the GP50 was introduced, the HT-B was dead within EMD, even though there is literature that suggests otherwise.
By that point in time, 4 axle locomotive production was dwindling and the truck design effort was focused on developing the radial steering trucks. If you were designing a 2 axle truck today, the GE P40/P42 truck or the EMD DE/DM30AC truck might be typical of what a new design would look like. Not the fabricated frames necessarily, but the elimination of friction wear surfaces such as the pedestal liners, bolster chafing plates, swinghanger bearing blocks and bushings, etc. in favor of rubber bushings that give consistent performance over their wear life.
Dave
Because the E unit had two engines I was wondering why it didn't have twice the horsepower as the F unit but you explained why ( i.e. smaller engines). Thats everyone for the information.
The EMD "F", "GP" and "SD" series (except the SD45) had one 16 cylinder diesel engine.
The EMD SD45 had one 20 cylinder diesel engine, as did the F45 and the FP45.
The EMD "E" series had two 12 cylinder diesel engines.
The EMD "DD" series had two 16 cylinder diesel engines.
OLTMANND got it right - the "A-1-A" truck was required for distribution of the weight of the then heavy "E" units. The very first of EMD's passenger locomotives (EMD #511 & #512, B&O #50, ATSF #1 & #1A) had two Winton 12 cylinder 201-A diesel engines and were on "B" trucks. With the introduction of the "E" series in 1935 EMD also went to the A-1-A truck.
The EMD FL9 locomotives have a "B" truck under the front and a "A-1-A" truck at the rear. Again, weight distrtibution.
jrw249 wrote:If a F unit has 4 traction motors and an E unit has 4 traction motors then why does the E unit have 2 diesel engines and the F unit only has one diesel engine.
More HP!
An F7 has a single 16 cyl engine making 1500 HP and an E8 has 2250 HP.
An F9 has 1750 HP and an E9 has 2400.
For more Faster Accleration and also to since they were Passenger power usaly they were over powered normally.
The idler was mostly to hold the locomotive up. An E8 is too heavy for 4 axles.
oltmannd wrote: Those equalized A1A trucks have a bazillion parts to them, and getting at the brakeshoes on the ones with the drop equalizers is a big pain. The 4 axle Blomberg has too many parts. The A1A has about double.I wonder if the patterns for the EMD or AAR style A1As are even around anywhere.....MP got the job done on 4 axles - good enough for the commuter market, anyway.
Those equalized A1A trucks have a bazillion parts to them, and getting at the brakeshoes on the ones with the drop equalizers is a big pain. The 4 axle Blomberg has too many parts. The A1A has about double.
I wonder if the patterns for the EMD or AAR style A1As are even around anywhere.....
MP got the job done on 4 axles - good enough for the commuter market, anyway.
The EMD A1A patterns were scrapped years ago. You are exactly right about the number of parts in both the A1A and the GP swinghanger trucks - no one today would design a truck like that. Too many wearing surfaces that are expensive and difficult to restore during rebuild. Look at the HTCR - no wearing parts to weld up and machine, just change bushings and some bolt-on wearplates and it is back to new condition.
beaulieu wrote: oltmannd wrote: What you say is exactly right for a freight only SD70MAC, but those Alaska SD70MACs might be a special case, since they are "dual mode" need the output of one inverter for HEP. Very clever to go A1A-A1A on one inverter in passenger mode. Don, shame on you, you have knowledge about locomotives, each invertor is designed to power three axles, you must have some idea of the complications of the additional wiring and serious software changes that would be required to make one of the invertors power 4 axles when in HEP mode, and only 3 motors when in normal mode. The ARR HEP MACs are a cheap and dirty modification to get a combination freight and passenger locomotive. To shift one invertor to HEP just requires software changes to allow them to work at different settings, to allow one to power 4 instead of 3 would require some fancy switchgear and a lot of extra cabling. Remember the front invertor powers the front truck of the locomotive, the rear invertor powers the rear truck. You would need six cables running from the front invertor to the rear truck (three for each motor), and they would only be used when the locomotive is in HEP mode. The invertor that powers either three or 4 axles would have had to be custom designed, and would have cost a great deal of money, and to boot it would be non-standard compared to the rear one and those used in the non-HEP equipped in the ARR fleet. Something like what is proposed would be easy with a GE AC4400CW where you have one invertor per axle, and all 6 invertors are in one compartment adjacent to each other, but in the SD70MAC the invertors are located at each end of the long hood with the engine compartment inbetween. It is totally impractical in a SD70MAC or a SD70ACe. Remember the ARR went through some hoops to get non-Tier II compliant SD70MACs rather than SD70ACes for parts commonality reasons. That is also why the GP49s departed rather than the less fuel efficient GP40-2s.
oltmannd wrote: What you say is exactly right for a freight only SD70MAC, but those Alaska SD70MACs might be a special case, since they are "dual mode" need the output of one inverter for HEP. Very clever to go A1A-A1A on one inverter in passenger mode.
What you say is exactly right for a freight only SD70MAC, but those Alaska SD70MACs might be a special case, since they are "dual mode" need the output of one inverter for HEP. Very clever to go A1A-A1A on one inverter in passenger mode.
Don, shame on you, you have knowledge about locomotives, each invertor is designed to power three axles, you must have some idea of the complications of the additional wiring and serious software changes that would be required to make one of the invertors power 4 axles when in HEP mode, and only 3 motors when in normal mode. The ARR HEP MACs are a cheap and dirty modification to get a combination freight and passenger locomotive. To shift one invertor to HEP just requires software changes to allow them to work at different settings, to allow one to power 4 instead of 3 would require some fancy switchgear and a lot of extra cabling. Remember the front invertor powers the front truck of the locomotive, the rear invertor powers the rear truck. You would need six cables running from the front invertor to the rear truck (three for each motor), and they would only be used when the locomotive is in HEP mode. The invertor that powers either three or 4 axles would have had to be custom designed, and would have cost a great deal of money, and to boot it would be non-standard compared to the rear one and those used in the non-HEP equipped in the ARR fleet. Something like what is proposed would be easy with a GE AC4400CW where you have one invertor per axle, and all 6 invertors are in one compartment adjacent to each other, but in the SD70MAC the invertors are located at each end of the long hood with the engine compartment inbetween. It is totally impractical in a SD70MAC or a SD70ACe. Remember the ARR went through some hoops to get non-Tier II compliant SD70MACs rather than SD70ACes for parts commonality reasons. That is also why the GP49s departed rather than the less fuel efficient GP40-2s.
Mea culpa! You are right. Lots of cable and switch gear. Also, would have to match wheels on all the axles, not just all the axles on one truck. Big pain.....
oltmannd wrote:What you say is exactly right for a freight only SD70MAC, but those Alaska SD70MACs might be a special case, since they are "dual mode" need the output of one inverter for HEP. Very clever to go A1A-A1A on one inverter in passenger mode.
beaulieu wrote: carnej1 wrote: Interestingly there are some modern "A1A" Passenger units in North America. The Alaska Railroad's SD70MACs have the ability to switch one of the AC Inverters from traction to HEP for passenger train service. When this feature is selected one traction motor on each truck is cut out, making them "A1A". For freight the engineer switches the electrical system back to standard CC configuration.It's a clever way to use the units electrical capacity and have plenty of "hotel power" available without needing an auxiliary genset.The reason for the disappearance of the A1A truck is related to the need for weight on the powered axles, too much power for too little weight means the wheels will slip. Of course you could limit the power at lower speeds, but US passenger cars are relatively heavy, compared to European designs.
carnej1 wrote: Interestingly there are some modern "A1A" Passenger units in North America. The Alaska Railroad's SD70MACs have the ability to switch one of the AC Inverters from traction to HEP for passenger train service. When this feature is selected one traction motor on each truck is cut out, making them "A1A". For freight the engineer switches the electrical system back to standard CC configuration.It's a clever way to use the units electrical capacity and have plenty of "hotel power" available without needing an auxiliary genset.
The reason for the disappearance of the A1A truck is related to the need for weight on the powered axles, too much power for too little weight means the wheels will slip. Of course you could limit the power at lower speeds, but US passenger cars are relatively heavy, compared to European designs.
Don't forget that when all those A1As were being built, the norm was axle loadings from 70 ton frt cars. Now it's 100+ tons....
beaulieu wrote: carnej1 wrote: Interestingly there are some modern "A1A" Passenger units in North America. The Alaska Railroad's SD70MACs have the ability to switch one of the AC Inverters from traction to HEP for passenger train service. When this feature is selected one traction motor on each truck is cut out, making them "A1A". For freight the engineer switches the electrical system back to standard CC configuration.It's a clever way to use the units electrical capacity and have plenty of "hotel power" available without needing an auxiliary genset. This isn't true, on the SD70MACs with HEP you cut out the power to one whole truck, making the locomotive a C-3, rather than an A1A. The SD70MAC has two traction invertors, one for each truck, not three for pairs of axles.
This isn't true, on the SD70MACs with HEP you cut out the power to one whole truck, making the locomotive a C-3, rather than an A1A. The SD70MAC has two traction invertors, one for each truck, not three for pairs of axles.
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