I don't have all these locomotives to compare. So far my only Z scale loco's are a ABA set of MT F's. I see most here say the SD70 runs differently. Does anyone know why? (different motor maybe?)Can't be just because it isn't brass. Also can anyone with a SD70 measure the long hoods width for me. I would guess this will end up being the same width of the soon to be out GP7. Someone said the GP35 runs well with the F7, but I thought the F7 was considered a bad runner and the GP35 was much better. Do they doth run the same speeds? I think my F7's run great, nice and slow and this was before I installed wheel wipers. At first one was tilted to the side, but that was fixed by bending the inner frame wipers to have equal pressure. Thanks
Chris, The SD70M is a much different design than anything else out there in Z scale. It has a very light frame so in order to improve the pull power (quite good, reports of between 40 and 60 cars) it uses traction tires. It is also geared for much slower speeds than anything else in Z scale. Good prototypical slow speed performance, but as a comparison, it is about half as fast as the MTL GP35 (or other AZL brass) at the same voltage. The GP35's will crawl quite nicely, but at a different voltage than the SD70M. MTL F7's - Yes this can get confusing. The MTL F7 is THE long time standard of North American Z scale. It pulls probably better than anything else in Z and is quite heavy. The older production units run well. A few years ago the the tooling for the wheelsets apparently started wearing out and the locos with these wheels wobbled and ran poorly. Since then, MTL has corrected the problem. Replacement wheelsets are available for something like 69 cents. Glen Chenier posted a very good explanation of this during chat on Z Central Station on Sunday. Glen is also the guy who came up with the improved wheel wipers. Hope this helps. Randy
hey guys, all of you who get "upset" about the width of GP35 :shade: how do you cope with track that should really be on 20mm centres (ie app 14ft) and thanks to Marklin is on 25mm (app 18ft)?? Chris
Chris, Are you talking about track center line spacing, like a on a double track line? My track centers are 13 Z scale feet just like the abandoned Erie double track main is through my back yard. http://www.rr-fallenflags.org/el/dwg/40-12533-1.gif Even if using other track (mine is handlayed C40) you can trim the ends of turnouts to get the spacing you want. Randy, Thanks for the info. Traction tires aren't bad if their done right. Can't imagine something slower than the F7, but I'll take it. (although not good for MUing I guess) Lower gearing could help it pull as well.
Chris, yes I was talking about centre line spacing and yes I know the quality of your work (I aspire to follow your example), but 99% of the guys insist on 25mm being "the standard", which makes it look so Z like :sad: This is my source: http://prr.railfan.net/standards/ Chris
We use 1" spacing because that's what the Z-Bend Track Standard is. Just like the N-Trak guys use a 3 track mainline, ugly as that is, because it is their standard. I mean, you could always use whatever you want on your home layout, unless you use sectional track.
John, Chris, Randy, et al. : the SD70 runs "slower" because of loading of the motor. This was first reported on the forum by Robert Ray and later on the Trainidini (or whatever that Euro mag is) by another person. The motor is coupled to the trucks by a flexible tube, not a metal rod. The alignment is not so good. Rob opened up the pockets or ground down the plastic bushings to let it align better and they run about 2x faster. I was shocked to see the speed difference between the original and mine. AZL knows about this but may take some time to make it a manufacturing change. For now, they run a bit more "prototypical" speed A little work and you can have a Marklin mode engine.
Jeff, I have read Robert posting, and even got on my knees to beg to do the modification for me, but he said something about the need to go to sleep. I AZL knows about the issues with this engines, so I am eager to see the performance on the next release. I hope the long period between the initial release and the BNSF release is due to Ajin correcting some of their manufacturing problems. I think the SD70 is a good engine that AZL can make even better. After all, I am a z scale modeller, and I want AZL to sell a lot of engines. That way, they can make more different type of engines for us.
Chris, This is a bit of a mixed bag. Just over half of my F7s match up well with the GP35. The other half is a mixed bag. Some of them just need a bit of tweeking (frame wipers, wheel guage, typical stuff), but at least a couple of them are terminal. From the sound of it, your F7s should be fine. I find the GP/F7 combo to be mutually beneficial. The F7s provide unparalled pulling power and the Geep helps the F7 through any rough spots a low speeds (including starting). It's amazing what a little nudge can do. I thought my F7s behaved well at low speeds, until I saw the GP35. The pair can't go as slow as the GP35 alone, but quite a bit slower than the F7 alone. Dan S.
Dan, interesting that you say the GP helps you thru the rough spots. Everone says the F7's were the poor runners due to electrical pick ups but the GP's use the exact same trucks ! The motors sure make a difference, like Marklins 3 and 5 poles do.
The MT GP35 does not have the same trucks as a F7. I asked Joe if I could buy the wipers off a GP35 for my F7, he replied that the trucks are not the same. Perhaps the sideframes are though(?) I have seen a photo online somewhere of the GP35 truck with the sideframe removed and it was different than my F7.
Jeff, Only the truck sideframes are the same (plastic piece with couplers). The trucks of the GP-35 are greatly improved pick-up wise. Unfortunately, as Chris said, the Geep truck won't work on an F7. In many ways, the F7 truck mechanism is "overcomplicated" compared to the Geeps. I don't know what the original designer of the F7 truck thought it would be rolling over, but it has floating axles, it pivots for tracking, but it also has pivots to rock from side to side and front to back. I't an all terrain truck. The Geep truck has pivot points to rock from front to back, and the only side to side is the inherant play in the truck socket. This design leaves plenty of metal on the chassis halves for the electrical contacts to ride against. A much cleaner design. Dan S.
One thing about the F7 that impressed me was the barrel gear. This gets a nice amount of reduction in a small space. Those trucks look like they could run on a roller coaster. About motors, there are good 3 pole motors and bad 5 pole motors. In N scale Model Power recently made a bunch of steam locomotives with 3 pole motors, they run great. I'm not up to date on Maxon motors that I think MT used in the GP35, but I have a bunch of small Faulhaber coreless motors with 7 poles. What brand motors do AZL locomotives come with? I know Ajin likes to use Mashima motor, but they are too big for Z scale. Other than Yahoo, are there any sites showing Z scale AZL and MT locomotive tear downs? I've seen the F7 sites.
This one is for the F59PHI http://www.nn3.ca/nn3-diesel-2.htm I wished all z scale chassis were design like this. It is so easy to dissasemble. It's a breeze to maintain this engine.
As far as I know, the sideframes are the same: myself I first purchased a Marklin style coupler-equipped GP35 as this sample was the only available where I was, and I had spare sideframes with MTL couplers in stock in my spare parts box. I easily changed them, I only had to remove the two small screws underneath and to put them back again to hold the new frames. There was no issue, other than finding the correct paint to apply on the original black plastic sideframes. Dominique
Looking at the AZL SD70, the axles look like they're really set up for good simple pickup: all three simply sit in a hole. Little slop, nearly almost always making contact on the top due to weight on the truck. The F7 and GP trucks sure looked the same holding them side by side and looking at the bottom but I did not take the GP truck out of the chassis to look at the top and wipers. I'll be doing that soon. If they are not the same, we need a spare parts for the GP, something we currently do not have, besides the plastic outer and wheels. Gears may be the same. Yes that internal planetary gearing is great for size and torque. The Marklin is still the easiest to take completely apart, especially just the trucks. Shell, one push-pin axle and it's in your hand (or the floor). Snap the shell off the truck, 2 more push-pin axles and everthing is apart. Can't beat that for simplicity.
Most of AZL's line uses 8mm Faulhaubers. The wide body locos use either 10mm Faulhauber or 10mm Mabushi (I think). Rob
