So, I bought two Kato SD70M locomotives. Normally Kato locomotives take an MT 2004 (old number) underslung coupler. Since my old hands are not as adept as formerly, I got the preassembled ones, 2 pair for about $13.00+. Yet when I mounted them, they were about 1/2 of a coupler height too high. I rechecked everything. I also ordered two of the Kato SD40-2's and mounted the MT underslung couplers and had no problems. The couplers were even with the adjoining cars. When I coupled the SD40-2 and the SD70M together the SD70M coupler was again about1/2 of a coupler too high. Normally I would file the bottom of the locomotive's coupler pocket to lower the coupler but before I did that, I thought it best to see if anyone else had a similar issue or possibly another solution.
So I have two Kato SD-70Ms. Took a look and turns out I had converted them to Microtrains differently. One looks like it is using 2004s. That one has the top a millimeter high against my coupler guage but the bottom is on. The other one I used 1016s and that one is maybe a millimeter low. Both are close enough that they operate ok. Maybe try the 1016s if the 2004s are too high.
This question comes up every so often here. My best answer is probably going to be one that you don't want to hear - it involves coupler assembly. As I posted earlier this year: https://www.trainboard.com/highball/index.php?threads/mtt-2003-or-mt2004.158095/#post-1326222 If you want a slightly easier workflow than I use, consider the use of the 1015 coupler internals in the 2004 box. Simply assemble the 1015 as normal, using the 2004 box, and use the OEM Kato coupler clip. Drawback of this assembly method is you end up with spare 1015 boxes and 2004 internals. Also costs twice as much. I'm cheap so I use the 2003 assemblies, as recently as two weeks ago.
I have a stash of MTL 2004s specifically for Kato locomotives. Many Kato locomotives have their couplers mounted too low (for MTL height gauge standards). The 2004 isn't perfect height-wise but still allows a height tolerance that guarantees reliable coupling under virtually all operating situations, whereas mounting a standard-slung coupler like a 1015 will more likely result in unintended uncoupling. In a perfect world MTL would make an underslung coupler that doesn't have the knuckle quite as high so it would be more compatible with MTL coupler gauge standards, but until then the 2004 is a reasonable compromise.
I had a similar situation with my SD70M and an SD40. The couplers were all over the place.........the only combination that worked was to couple nose to nose, which isn't really an option. the 2 locos wouldn't couple to each other any other way and wouldn't couple reliably to cars either. I don't remember the exact combination I ended up with, but it involved a 2004 and a 1016 on each loco, and it wasn't the same combo for each loco.......so one had a 1016 front and a 2004 rear and the other was the opposite. I have something similar on my NW2s . I have a pair that I run as an MU'd pair in my yard. I was having trouble with the standard Kato couplers coupling and uncoupling when switching, so decided to convert to MTs. since the locos stay coupled, I left the standard couplers in place, but replaced the outer couplers with 2004s......problem is one coupler is about 3/4 or a coupler high and the other is perfect. I'm looking at doing the 1015/1016 swap . I checked and everything else is correct.....shells are down tight, trucks are fine, ect.
I've had the same coupler height problem with my Kato SD70M's. To be correct there is nothing wrong with the loco , the problem is the MTL coupler recommendation. 2003's are the correct height after modification. I have had a drilling jig to modify the top cover in the 2003's but I have yet to get one closed up long enough to install it. I'm not steady enough to weld the body and top shut. I'm trying to glue it together with no luck so far. I did disassemble a factory assembled 2003 and I noticed it was not welded or melted but was held together with a green looking glue. My guess is the adhesive may be a plastic drain pipe adhesive.......................
I would recommend that you consider purchasing unassembled 2004 couplers and use those boxes with your 2003 internals; they come pre-drilled and are better at staying assembled without glue or welding.
I just bought a conversion kit (MT 0010251) for a Kato E8 The kit comes with 2 pairs of couplers for the truck mounted rear, and 2 pairs for the front. I'll assume the fronts are 2004s since that is listed under the part number, but the important thing, is whatever they are, they have snap on lids. Odd thing is the instructions state to use a soldering iron to glue the lids on.......but they very definitely snapped on and stayed together thru a lot of handling when I installed them.
Okay I managed to locate the problem. According to my measurements the opening for the coupler on the Kato SD70M is .06" too high. That would correlate to 9.6 inches on the prototype. This I confirmed by coupling the SD70 to a SD40-2 and measuring the difference in height of the SD70 coupler over the SD40-2. Again, it was .06 inches. Looking at a head on view of the SD70 alongside a SD40 the difference in height of the coupler is quite obvious with a larger area below the coupler. It looks like I can file down the area below the coupler and add a .06 shim to the top of the coupler. I'm thinking that the retainer clip would not be long enough to hold the coupler in place so I might have to resort to a screw to do the task. Still, some work to do.
I don't have any in front of me to measure, but what is the difference in knuckle height between a 2004 and a 1015 coupler? I think the clip will fit either coupler box, but the hole in the front of the pilot may need to be filed a bit to fit the 1015 box, especially on older locos. But I've never had to file an opening, and as I said earlier, I have a number of Katos that have both couplers fitted (sometimes both on the same loco). But regardless, using a 1015 coupler would probably fix the issue and may do it with no other modifications.
Looking at MT's conversion chart the note https://micro-trains.com/publicfiles/conversions/sheet007.pdf says "Open pilot in lower corners to make fit easier". Not sure what that actually means but could there be something on the shell that pushes the coupler up too high and has to be carved off?
Original Kato couplers do not have a box......they just have a coupler that's tensioned by a metal strip and held in place by the clip. The hole in the pilot has slightly rounded (VERY slightly) corners and filing the corners sometimes helps. I've never done it, but the couplers are a very tight fit and you have to be very careful pushing them into place. You can also slightly file the bottom (box side) corners of the coupler. The rounded corners in the pilot are simply easier to mold than a perfectly square hole (they release from the mold better). You CAN replace the clip with a screw and that works just as well for holding the coupler on, but the screws that come with the couplers are WAY too long and if you just crank one in, it will punch thru the walkway and stick up almost 1/8 inch. I've also seen shells broken when the screw punches thru. I find that if I cut the screw off at a slight angle, it will almost act as a tap and help the screw bite into the shell and cut threads........I've never tapped any of my shells I've converted to screws.
I'm willing to try anything once. So, I inserted a 1015 coupler onto the SD70M and tried to couple to a MT gondola. The 1015 coupler could not engage the coupler on the gondola as the bottom of the 1015 coupler was above the top of the gondola's coupler. This was a total mismatch in height. With the usual 2004 coupler at least the bottom half of the 2004 coupler engaged the top half of the gondola's coupler. Right now it looks like I am going to have to file .06" off the bottom of the coupler opening.
That's really strange, as the 1015 coupler should sit at least 1/2 a coupler lower than 2004 (given they are attached to the same loco). The coupler boxes are the same thickness on the bottom plate, so there's virtually no way the 1015 should sit higher, especially that much higher. Not saying it's not happening, but there's something else going on if that's the case. I double checked my SD70M, and I ended up with a 2004 on the front and a 1015 on the back......both check out with a MT height gauge. It also lines up perfectly with the SD40 I normally run it with........but the 40 has 2 2004 couplers (I was wrong earlier.....I thought it had one of each coupler as well) and although the rear 2004 couples perfectly with the SD70, the front coupler is the opposite of yours and sits a half coupler too low, which is also odd since it SHOULD sit high.
I have used the 2003 + 2004 coupler parts mix and it works great ............. I'm just too cheap when I look at all the left over parts.
Veeeeeeeeery interesting news on those E and F unit (2000) front couplers. . I just checked MTL's web site and they are temporarily out of stock. I will add a pack to my next order from Micro Trains. I see the rear couplers are 1128's. They are a pretty useful coupler so they won't got to waste. The instructions say to use Walther Goo for assembly .................. that stuff wouldn't be green by any chance ?
Try this, measure the distance from the bottom of the pilot to the bottom of the coupler opening on the SD70M and the SD40-2. On my SD70M I get .15 inches while on My SD40-2 I get .08 inches. Allowing for the possibility of slight error in measurement, this almost matches the difference I measured earlier in coupler height (.06 vs .07). This is the same on both of my SD70M units. Like you I figured that the 2004 coupler, because they are underslung, would be higher than the 1015's. But it's the other way around, the 1015's sit much higher. Seems counter-intuitive. By the way I checked an Atlas locomotive which do take the 1015 couplers and found the distance from the bottom of the pilot to the bottom of the coupler opening to be .10 inches. I think I will give Kato USA a call. See what they say.
308GT.......There was a definite click when I pushed the lid on the coupler, and they took some pretty rough treatment getting pushed thru the pilot when installing them and they stayed together. As I said, I can't tell you what they are because they were packaged as a conversion kit . Interestingly......under the part number there is a 2004 in parenthesis, but on the back, it says "contains 2 pair 2001 couplers.....4 knuckle shanks,4 lip shanks, 4 draft gear boxes, 4 lids.........and then it goes on to say the 2 short shank couplers are to be used for wide radius curves and the 2 long shank couplers are to be used on short radius curves. ????????????? That's NOT what was in the kit. Inkaneer.....I'm not sure you can use the bottom of the pilot to the bottom of the coupler opening to determine anything . I have locos where the pilot barely clears the tops of the rails (I have some GP9s that the pilot actually hit if there's ANY irregularity at the rail joiners) and others where it clears by quite a bit. The couplers need to be a fixed height above the rail, not above the bottom of the pilot since that distance seems to vary. Here's a picture of 2 locos, one an Atlas with a 1015 and one a Kato with a 2004...... the 2004 has a much taller knuckle (which surprised me), but the bottoms of the knuckles are the same height. harder to see is the bottom of the Atlas pilot is lower than the bottom of the Kato........which you would think would dictate needing the underslung coupler to raise the knuckle to allow for the lower pilot , but it doesn't.
Still the distance is different on the SD70M than the SD40-2's. I would think the distance should be the same because if it were the same then the 2004 coupler should work on the SD70M. But it doesn't. Later I'll measure to the top of the coupler opening from the railhead as the clip holds the coupler up against the top of the opening. There is little or no wiggle room for the coupler box in the opening.
Okay, I consulted MT's website and observed that both the 1015 and the 2004 should have the same height from the railhead to the midline of the coupler. That is, according to MT, .216 inches or 5.5 mm. However, in trying to measure this on the SD&0M and the SD40-2, I incurred some inaccuracies mainly due to determining the midline of the coupler and the fact that even a pencil line or an ink line could throw off the measurement. So I went with the measurement to the top of the coupler box as I indicated in my above post. There I got a reading of a difference of .055 inches which is almost the same as my prior measurement of .06 inches for the coupler height difference. It seems to me that the problem lies with the locomotive and not with the coupler. My next step, after the weekend, will be to contact Kato USA about this.
