7mm US model dabblings

richard carr

Western Thunderer
Yes sorry I should have said Canadian Pacific in La Crosse.

Anyway, Sunday we got early and went back down to the CP yard to see what was happening, it would appear the trip freight starts work at 7am as he got busy then

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This is the one that struggled on Saturday to get his train across the Mississippi. He soon disappeared off to find something.

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We didn't have to wait long before a grain train turned up.

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He seemed to be on the wrong lines the BNSF goes the other way in La Crosse.

After this we set off for Portage Wisconsin, but didn't find a lot there other than a nice breakfast and a chance to listen to the German GP on BBC radio i player, what a race.

We went to look for what appeared to be a crossing of 2 tracks on the flat on the map but this is what we found.

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An old bridge over a very old track beneath it, nothing happening here so we headed to the Byron Hills.

Once we got to Byron it didn't take long to find a train, this is a Canadian National Route but still uses Illinois central liveried locos.

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We saw these two go by at the main road in Byron and chased back to photograph them, it wasn't long before they turned up.
 

richard carr

Western Thunderer
We then spent the rest of the afternoon waiting for train going up the hill, it is a 1% grade for about 10 miles these were making a fantastic noise.

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We then moved on to the next road to cross the railway.

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By comparison these locos were almost silent.

We then went to the main road crossing in Byron and after about 30 minutes a train arrived inthe opposite direction.

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After this we started back to West Chicago still about 150 miles away, but just after leaving Byron we saw this parked up in the distance and went to investigate.

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He seemed to be having a problem withthe point from the loop but having got out of the cab and messing with things it must have been working as he came out of the loop.

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Then he went back again and then finally went on his way.

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After this we drove back to West Chicago to see the Big Boy.
 

Jordan

Mid-Western Thunderer
The funny green thing of course is 1:43 scale whereas the excellent grey monster behind is 1:48 scale. Now, if they were both the same scale :eek:
Quite. The GWR loco should be considerably smaller than the US one. Consider that when they moved the A4 Dwight D. Eisenhower a few years ago to visit the UK, they put it on a standard flat car - and it was still within the US Loading Gauge. :rolleyes: :D :p

Byron Hill is ex-Soo Line territory :cool: although back then it was single track. It went to Wisconsin Central after 1987, and was doubled some time later.
 

mickoo

Western Thunderer
There's three reasons why the second train might be quieter.

There's two trains that are quieter, the first is CN, BNSF, the second CN,CN.

The second is a pair of Tier 4 GEVOs, the first pair are Dash 9's, looks like a cigar band BNSF unit trailing and I'd be expecting these to be bellowing at the skies, Dash 9's are not quiet. CN 2716 is from the batch to have tear drop windscreens, CN being the only railroad I believe to feature this type of screen.
I've not found definitive proof yet, but believe it is the same screen found on EMD models with tear drop screens, the grandfather being the DD40AX. It could be CN were keeping spares stock to a common standard, or prefer the extra visibility the tear drop gives up close.

The Tier 4 engines have tighter emissions and volume levels which might account for their reduced volume.

There's 8,800 HP on tap as opposed to 6,300.

And probably most important, the second trains are imtermodals; intermodals are generally not as heavy axle for axle as a manifest.

Train length might be a contributing factor, longer is sometime better. If you are at the top of a hill that is 2 miles from the crest of one behind, then a short 5,000' train will all be on the grade from the bottom of the sag. A 10,000' train will have half coming up and half going down the previous grade.

Intermodals are usually longer than manifest as tonnage is rarely the limiting factor, it'll be siding length unless your on a high density main like Transcon 2 or the Overland and then it'll be train dynamics, stretching, bunching, stringline etc. BNSF run the longest in the world at 16,000'.

In Florida on the A line around Wildwood it's quite a switch back and mostly single line, so train lengths are limited by sidings at 10,000'. A intermodal will easily get along with one or two GEVO's up front, A manifest will have four and it'll take all four to get it moving.

There are heavier trains axle for axle, oil, coal and stone, there are lighter, lightest are trailer trains (pig liners) or autoracks.
 
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mickoo

Western Thunderer
Google is an even better one, just type CN 2716 for example and all the info and photos are there to digest. Best put safe search on first if your in public, random letters and numbers can often bring up rather obscure/bizarre images.
 

Brian McKenzie

Western Thunderer
There are a few interesting snippets in this mid 1950s film - leaving aside much cheesy dialogue and (amusing) attitudes of the day:
15:40 Loading ice into reefers
18:45 Mailbag collection
21:12 Brakedust (?) while descending grade
An enduring memory of the Milwaukee Road electric operation is of the smoke pouring off trains descending in the Rockies.

(This film was a diversion off the excellent Youtube channel by 'Machine Thinking' [W. Francis] on the construction of an early micrometer attributed to James Watt.)
 

Brian McKenzie

Western Thunderer
Well, I was curious about the smoke seen coming from descending freight trains of years ago (refer previous message). It's not brake dust, but from hot oil and grease. The answer was found here:

What was "brake shoe smoke", anyway?
Most of the time it was oil & grease on the shoes & wheels heating up & smoking. Most of those older cars had plain bearing trucks instead of roller bearings. The journal box oil was thick, almost like 90 wt, and it would usually leak past the seal at the back of the box. When it did (either from a worn out/missing seal or from over filling) it ran down the plate of the wheel & onto the brake shoe & surrounding parts. When the brakes were set, the shoe would heat up first, then after a while the whole wheel would get hot, and the accumulated grease & oil would start to cook off.

A Rio Grande brakeman once said "some railroad crews worry about brake smoke; up here (in the mountains) we worry when we don't see any".

I dug out some old slides, but didn't spot any smokey ones:

Milwaukee boxcabs running downhill into Avery, Idaho. 20 August 1972
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Boxcabs at Avery, Idaho 19 August 1972 (lit using car headlights)
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UP6934 "Centennial" at Pocotello, Idaho 21 August 1972 (scrapped 1986)
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Eastbound "Rio Grande Zephyr" out of Grand Junction, Colorado 22 August 1972
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UP E948 + 914 at Cheyenne, Wyoming 24 August 1972
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mickoo

Western Thunderer
Nice slides, always had a bit of a anorak for the MILW box cabs :thumbs:

I'm sure the smoke can be either, if it's a blue colour then it'd probably be oil and grease from hot boxes as you note, if it's black or brown it'll more as likely be brakes.

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Most modern trains do not seem to exhibit smoke during descent due to modern engines having very efficient dynamic braking, however, on Transcon 2 BNSF seem to set their brakes on particularly heavy types of block train, specifically oil, coal, and sometimes the big 18,000t grainers. Both UP and BNSF set brakes on these trains down Cajon.

The only smoker I've seen though is this oil train dropping down off the Continental divide just west of Flagstaff, given that it's all modern roller bearings and the colour was light brown I'd tend toward brake shoe dust. Interestingly the engines were not in dynamic mode, the whole train was being held back on the brakes, I'd presume the dynamic brakes are there in case it gets away from it's self or as added braking if required. The summit is only a mile, maybe a little more around the corner so I doubt the full weight is on the grade, therefore as more weight gets on the downhill side then maybe dynamics will be used.

The grade eases just east of here at Flagstaff, say three miles way so the grade is short and one hopes the brakes won't get too hot, Cajon is something like 15 miles from Summit to Keenbrook/Glen Helen where the grade eases.
 

Big Train James

Western Thunderer
I'd have to go back and brush up on my dynamic braking know-how, but I'm under an impression that in modern practice, almost all train braking on descent is supplied by the locomotive dynamics, rather than mechanical braking. I seem to recall a rule of thumb to the effect that the number of units required to lift a train up a grade will always have enough dynamic capability to control it on the way back down. I'd have to dig in order to quote a source on that though.

To that end, I can't think of a single time railfanning in Colorado that I recall seeing brake shoes applied on trains descending from the mountains. However, train tonnages seem to have gone up in the past several years, so maybe the braking demand/tonnage equation has swung the other way.

One other consideration is train speed. I don't think dynamics are effective under a certain rate of speed. So in that case I suppose mechanical braking would be the only option? Although I think the effective minimum speed is quite low, so trains would have to be crawling to fall into this category - say under 10 mph?

I'd normally attribute any dust to the swirl of air from trains at speed, or from locomotive sanding from at startup or on the climb.

All of these observations or suppositions are based strictly on the modern roller bearing era.
Jim
 

mickoo

Western Thunderer
I'd have to go back and brush up on my dynamic braking know-how, but I'm under an impression that in modern practice, almost all train braking on descent is supplied by the locomotive dynamics, rather than mechanical braking. I seem to recall a rule of thumb to the effect that the number of units required to lift a train up a grade will always have enough dynamic capability to control it on the way back down. I'd have to dig in order to quote a source on that though.

To that end, I can't think of a single time railfanning in Colorado that I recall seeing brake shoes applied on trains descending from the mountains. However, train tonnages seem to have gone up in the past several years, so maybe the braking demand/tonnage equation has swung the other way.

One other consideration is train speed. I don't think dynamics are effective under a certain rate of speed. So in that case I suppose mechanical braking would be the only option? Although I think the effective minimum speed is quite low, so trains would have to be crawling to fall into this category - say under 10 mph?

I'd normally attribute any dust to the swirl of air from trains at speed, or from locomotive sanding from at startup or on the climb.

All of these observations or suppositions are based strictly on the modern roller bearing era.
Jim
Trust me, the brakes were well and truly on ;) the noise is dreadful from the squeal and shoe chatter.

Every oil and coal train I've seen descending Cajon or the Continental divide has had brakes set firmly on and speed is very low, as you say, in the 10-15 mph range (maybe lower) and yes modern dynamic brakes go down (I'm not sure either but recall as low as 7 mph ?) to a low level these days.

Both oil and coal trains stop at Summit without fail, set brakes and then accelerate hard to get moving, they pass you at the cutting still pulling hard, but barely moving, and do not throttle back until Silverwood where the weight of the train begins to take hold.

I've not seen the big grainer descend Cajon so couldn't say if it has brakes set. Occasionally a manifest will set brakes, usually UP on the Palmdale cut off but BNSF will occasionally, other than that, the rest all descend on dynamics as far as I've witnessed.
 

mickoo

Western Thunderer
Well, back to the GEVO for a few days, the second test etch has been rumbling along in the background, but before I pulled the plug I decided it was time to consider the panels and hatches. Some are clearly going to be etched overlays, but it was the grills, pyramid stamped and pressed vent panels that were....and have been for many years for me.....the problem.

So as a little experiment I decided to have them 3D printed, they're okay, there's room for improvement I'm sure but their inclusion is still up for debate.

First the pressed vent panel covering the battery compartment. This was done as a very thin overlay, and I mean thin, almost transparent. The vents are a little over sized but that can be tweaked.
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However, as thin as it is, it's still too thick to replicate the real thing. There's two choices, sand it even thinner or make half etch recesses in the nickel silver steel work behind; more beer will be consumed whilst I ponder that solution.

Next up are the vents to the blower cab (GE calls each body section a cab, operators cab, auxiliary cab, blower cab, engine cab, radiator cab) this is pretty much standard across much of the production. Two vents are fitted here, a large (RH - Engineer) and a small (LH- Conductor) and the etch work already had openings here in the metal work.

The original plan was to etch something up, possibly with a tiny grill (with holes) formed into the sinusoidal waveform like the real thing, however, taking stock of life generally I decided it was too short so opted for a solid rendition.

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The grill flange is slightly to thick and it has a raised section on the rear to locate it into the hole in the etch work. The grill came out well...except the small blow holes at top right. Two options here, live with the slightly thicker frame, or, remove it and have the frame etched with a inserted (from the rear) grill section.

On the other side the smaller/shorter one.

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I also tested one of the shallow pyramid stamped covers as fitted to the Inverter cabinet (that's the big box behind the conductor on the LH side, always fitted to AC units but occasionally DC units, no idea why as DC units do not have inverters). Like the grills it has a raised locating section on the rear, but unlike the grills I didn't think ahead and have corresponding holes etched in the cabinet; hence it's standing proud a little.

It's okay, but like the others, the flange or it's thickness is not scale, you could probably form this from etch and scour lines on the inside to replicate the pyramid edges though you'd not replicate the large bolts held to secure it.

As before, there are two options, loose the locating lug on the back and then fit it into a half etched recess or loose the lug and sand it thinner.

Half etch recesses are okay but you never seem to get a perfect crisp edge with the part inserted into the recess, though I do have some ideas how to correct that.

That cabinet to the rear of the Inverter cabinet can also be replaced with a 3D print, currently it's just the core with no overlay on the model, I've no idea what's in here....I did know, but it (annoyingly) evades me right now.

There are many other objects that are certainly suitable for 3D printing, some of the grills in the radiator cab are fitted into substantially thick doors, there's also the headlight fitting and the cab control desks for example. All I need do is find the time to draw them up :p

And now some 1:1 stuff.

Four UP GEVOs pull hard to drag a standing manifest out of the siding on the Palmdale cut off at Cajon.

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Three BNSF GEVO's wheel a long double stack train through Hesperia toward Cajon pass.

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Five BNSF GEVO's (3x2) climb out of Victorville and over Natural crossover heading west.

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Big Train James

Western Thunderer
....However, as thin as it is, it's still too thick to replicate the real thing. There's two choices, sand it even thinner or make half etch recesses in the nickel silver steel work behind; more beer will be consumed whilst I ponder that solution.....

....As before, there are two options, loose the locating lug on the back and then fit it into a half etched recess or loose the lug and sand it thinner....

Half etch recesses are okay but you never seem to get a perfect crisp edge with the part inserted into the recess, though I do have some ideas how to correct that......
I would just etch all the way through. Then increase the hidden depth of the print to match the full thickness of the metal. Solder a strap across the opening from the back to act as a stop. If you can't have a flange that covers the opening in the sheet metal, then hopefully you can get the opening size dialed in to match the 3d print as closely as possible.

Alternatively, skip the soldered strap and add a flange to the 3d print that fits to the back side of the sheet metal. The same adjustments would need to be made to match the print thickness to that of the metal where it passes through, so that the X panel protrudes (or is flush) as required.

Often with thin cross section 3d prints for our scales, it's handy to think about increasing thickness rather than reducing it, as long as you can hide that extra thickness somewhere else.

Jim
 

JimG

Western Thunderer
Alternatively, skip the soldered strap and add a flange to the 3d print that fits to the back side of the sheet metal. The same adjustments would need to be made to match the print thickness to that of the metal where it passes through, so that the X panel protrudes (or is flush) as required.

From messing about with mixing 3D prints and metal frames, I would go along with Jim's suggestion. The thicker print might also reduce any chance of warping.

(Another) Jim. :)
 
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