decoder location

[ndbprr]

How hard would it be for the manufacturers to locate the decoder in the fuel tank instead of the top of the engine. That way a cover on the bottom could be removed and stop the having to disassemble the engine when service was required.

[ndbprr]

How hard would it be for the manufacturers to locate the decoder in the fuel tank instead of the top of the engine. That way a cover on the bottom could be removed and stop the having to disassemble the engine when service was required.

[Kent]

It problem could be done, but I think the loss of the weight would effect the operation and traction of the loco, perhaps too much.

[Kent]

It problem could be done, but I think the loss of the weight would effect the operation and traction of the loco, perhaps too much.

[ndbprr]

I disagree about the weight. The space now left in the top of the hood for the decoder could be filled with weight. They certainly don't show signs of top heaviness at this point. Besides, how many people consistently run 40 car trains. It really wouldn't be too hard to just turn everything upside down. the only aditional cost would be for headlight bulb leads which are usually about 4" when new any way. A well engineered unit could even have the bulbs in the fuel tank with a fiber optic or clear plastic path for the light to get to the headlight. Pop the cover on the bottom and do all maintenance at one location. Probably would be impractical on switchers but the road power should have plenty of room. A little cover like you TV remote that snaps out would give access and never be visible. It is very doable.

[ndbprr]

I disagree about the weight. The space now left in the top of the hood for the decoder could be filled with weight. They certainly don't show signs of top heaviness at this point. Besides, how many people consistently run 40 car trains. It really wouldn't be too hard to just turn everything upside down. the only aditional cost would be for headlight bulb leads which are usually about 4" when new any way. A well engineered unit could even have the bulbs in the fuel tank with a fiber optic or clear plastic path for the light to get to the headlight. Pop the cover on the bottom and do all maintenance at one location. Probably would be impractical on switchers but the road power should have plenty of room. A little cover like you TV remote that snaps out would give access and never be visible. It is very doable.

[nfmisso]

Moving the center of mass as you suggest would have an adverse effect on the trackability of the locomotives - the would derail more often. The current truck attachment method used on most plastic diesels requires the center of mass to be below the pivot point, so that the locomotive does not lean to oneside.

Besides, today, you just remove the cover (shell), and everything is right there, in one place.

[nfmisso]

Moving the center of mass as you suggest would have an adverse effect on the trackability of the locomotives - the would derail more often. The current truck attachment method used on most plastic diesels requires the center of mass to be below the pivot point, so that the locomotive does not lean to oneside.

Besides, today, you just remove the cover (shell), and everything is right there, in one place.

[Anonymous]

Yes - its very possible for manufacturers to put the DCC socket in the fuel tank, the big trouble is centre of gravity. Modern diesel models runs so well because to a large part they are well balanced, raising the centre of gravity by even a small amount will lead to problems, like tipping over on curves and derailing.

You only need to look at prototype locos to see how important a low centre of gravity is - one of the the heaviset components on a Geep, for example, the fuel tank is down below the main frame between the trucks.

[Anonymous]

Yes - its very possible for manufacturers to put the DCC socket in the fuel tank, the big trouble is centre of gravity. Modern diesel models runs so well because to a large part they are well balanced, raising the centre of gravity by even a small amount will lead to problems, like tipping over on curves and derailing.

You only need to look at prototype locos to see how important a low centre of gravity is - one of the the heaviset components on a Geep, for example, the fuel tank is down below the main frame between the trucks.

[Anonymous]

I have a HO Roco BR215 loco, and it has a milled space in the fuel tank expressly designed for a decoder, with a channel to run the wires up to the board. Seems to have enough weight. The fuel tank is plastic and snaps right over it. Very slick design. If you're in N scale, I don't know how it would work.

Gary

[Anonymous]

I have a HO Roco BR215 loco, and it has a milled space in the fuel tank expressly designed for a decoder, with a channel to run the wires up to the board. Seems to have enough weight. The fuel tank is plastic and snaps right over it. Very slick design. If you're in N scale, I don't know how it would work.

Gary

[ndbprr]

The center of gravity issue is absolutly bogus unless your diesels are built different from mine. The weight is all in the car body NOT at or below the trucks. Comparing prototype loco center of gravity is a red herring and doesn't apply to models - unless you are operating 100% accurate models with diesel prime movers and traction motors all scaled to 1/87th of course.

[ndbprr]

The center of gravity issue is absolutly bogus unless your diesels are built different from mine. The weight is all in the car body NOT at or below the trucks. Comparing prototype loco center of gravity is a red herring and doesn't apply to models - unless you are operating 100% accurate models with diesel prime movers and traction motors all scaled to 1/87th of course.

[BentnoseWillie]

"Absolutely bogus"? If you're unconvinced that where the weight sits is important, take a freight car and move the weight from the bottom of the shell to the top, and see how it tracks. A lower C of G makes for a better-running car in my experience.
Most of my HO scale diesels have the center of gravity well below the sill. You haven't mentioned your scale yet, but I take it you're in N scale, where split frames are more common? In HO, the frame can be lower-slung for a low C of G and still have adequate mass.

Judging by how you've handled our responses, you've made your mind up already, so why not take it to the manufacturers? Maybe they'll give your idea a try.

[BentnoseWillie]

"Absolutely bogus"? If you're unconvinced that where the weight sits is important, take a freight car and move the weight from the bottom of the shell to the top, and see how it tracks. A lower C of G makes for a better-running car in my experience.
Most of my HO scale diesels have the center of gravity well below the sill. You haven't mentioned your scale yet, but I take it you're in N scale, where split frames are more common? In HO, the frame can be lower-slung for a low C of G and still have adequate mass.

Judging by how you've handled our responses, you've made your mind up already, so why not take it to the manufacturers? Maybe they'll give your idea a try.

[Anonymous]

Would heat be a problem for a decoder in this location?
Although heat rises, I wonder about ventilation for the decoder.
I suppose the front and rear of the tank could have holes, but that might distract from the models appearance.

If heat is not a problem, it sounds like an interesting idea!

[Anonymous]

Would heat be a problem for a decoder in this location?
Although heat rises, I wonder about ventilation for the decoder.
I suppose the front and rear of the tank could have holes, but that might distract from the models appearance.

If heat is not a problem, it sounds like an interesting idea!

[ndbprr]

Moving a sheet metal weight from the bottom of a box car to the roof siginificantly raises the center of gravity. I accept that because the entire mass is being elevated significantly. The point being missed is that the vast percentage of weight in a model locomotive is already above the frame and is far larger than the weight used in a car. The amount of weight removed from a fuel tank and placed above the frame does not significantly change the mass or the center of gravity. I have taken the idea to three manufacturers none of whom responded in any manner and it was done in a nonconfrontational way. I don't want to mess with touching shells any more than I have to. The details are far too delicate to handle much abuse or contact. I am merely trying to think outside the box. I will argue against what I consider nonissues. I chose not to go into engineering calculations but I can support my opinion which happens to be fact. It is similar to the accepted notion that you can not run engines of differing speeds together because you will burn up one of the motors. I don't know anyone this has happened to and when asked on the internet on one of the major forums neither did anybody else. It is just accepted as fact without any documentation. I want a hobby where maintenance is as easy as possible and damage to the engine is minimized in that process. No my mind isn't made up but I may mill out a frame and replace the weight above the existing one. Maybe the next time you see a reference it will be in an article - probably followed by several letters saying it can't be done for adverse reasons :-).

[ndbprr]

Moving a sheet metal weight from the bottom of a box car to the roof siginificantly raises the center of gravity. I accept that because the entire mass is being elevated significantly. The point being missed is that the vast percentage of weight in a model locomotive is already above the frame and is far larger than the weight used in a car. The amount of weight removed from a fuel tank and placed above the frame does not significantly change the mass or the center of gravity. I have taken the idea to three manufacturers none of whom responded in any manner and it was done in a nonconfrontational way. I don't want to mess with touching shells any more than I have to. The details are far too delicate to handle much abuse or contact. I am merely trying to think outside the box. I will argue against what I consider nonissues. I chose not to go into engineering calculations but I can support my opinion which happens to be fact. It is similar to the accepted notion that you can not run engines of differing speeds together because you will burn up one of the motors. I don't know anyone this has happened to and when asked on the internet on one of the major forums neither did anybody else. It is just accepted as fact without any documentation. I want a hobby where maintenance is as easy as possible and damage to the engine is minimized in that process. No my mind isn't made up but I may mill out a frame and replace the weight above the existing one. Maybe the next time you see a reference it will be in an article - probably followed by several letters saying it can't be done for adverse reasons :-).

[BentnoseWillie]

You still haven't said what scale you're in or what engines you're working with, though you wasted half your post with an irrelevant discussion of locomotive speeds.

Rejecting explanations made in good faith while asserting that your view "happens to be fact" is in fact the opposite of thinking outside the box. Since you know so much more than we do, you go ahead, and good luck with it.

[BentnoseWillie]

You still haven't said what scale you're in or what engines you're working with, though you wasted half your post with an irrelevant discussion of locomotive speeds.

Rejecting explanations made in good faith while asserting that your view "happens to be fact" is in fact the opposite of thinking outside the box. Since you know so much more than we do, you go ahead, and good luck with it.

[Anonymous]

Note that the European manufacturers do often locate their decoders in the fuel tank/inverter box. However they also rely on deep NEM flanges to track well, and traction tires for pulling power,since their loco's are very light (My Atlas S-2 weighs roughly 3x as much as my Fleischmann Class 103 heavy electric, which is the size of an SD45).

Another thing which tends to cause problems for the lower location is motor mounts. Most North American designs have motor mounts in the location where you want the decoder, this is going to be a major design issue. I doubt that any manufacturer will throw away a proven chassis design to accomodate a possible 1 time change that the user may perform (Really, you're going to install the decoder, and then leave it alone, except for the occasional user who has a problem). Note that this location will also make rewiring the locomotive for different lighting (Ditch lights, relocation of headlights) and the addition of sound will be significantly more difficult with the fuel-tank location. Also, many smaller locomotives don't have a large enough fuel tank (RS units, switchers, smaller GP's, some passenger units) to accomodate the decoders.


The disadvantages of the lower location (Higher CoG, necessity to redesign chassis, more complicated wiring, more difficult sound installation) tend to outweight the advantages (Removing the shell no longer necessary to install DCC).

[Anonymous]

Note that the European manufacturers do often locate their decoders in the fuel tank/inverter box. However they also rely on deep NEM flanges to track well, and traction tires for pulling power,since their loco's are very light (My Atlas S-2 weighs roughly 3x as much as my Fleischmann Class 103 heavy electric, which is the size of an SD45).

Another thing which tends to cause problems for the lower location is motor mounts. Most North American designs have motor mounts in the location where you want the decoder, this is going to be a major design issue. I doubt that any manufacturer will throw away a proven chassis design to accomodate a possible 1 time change that the user may perform (Really, you're going to install the decoder, and then leave it alone, except for the occasional user who has a problem). Note that this location will also make rewiring the locomotive for different lighting (Ditch lights, relocation of headlights) and the addition of sound will be significantly more difficult with the fuel-tank location. Also, many smaller locomotives don't have a large enough fuel tank (RS units, switchers, smaller GP's, some passenger units) to accomodate the decoders.


The disadvantages of the lower location (Higher CoG, necessity to redesign chassis, more complicated wiring, more difficult sound installation) tend to outweight the advantages (Removing the shell no longer necessary to install DCC).