Ready Mix Plant Operations (Walthers Model Example)

Model Railroader Prototype information for the modeler
1

Curious about how the various ingredients get into a cement truck.

Looking at this picture of the Walther Blue Star Ready Mix Plant, it appears that aggregate would be loaded into the grade level grate, then conveyored up to the bin, where it gets dropped into the truck, along with water that is stored in the silo.

I’m assuming that the truck would drive to this facility with the cement/portland already in the mixer, then it mixes the ingredients in its mixer. Dry cement is not actually stored in a facility like this:

Walthers HO Blue Star Ready Mix - PJs Train Shack

If I had the space, I would model dry cement storage and loading silos somewhere nearby. And, rail cars could provide cement to that storage building, and aggregate to the building above. And I would want piles of different sizes of aggregate close to the conveyor, and a loader nearby to fill it…if I had enough space.

Is this how y’all see a facility like this functioning?

2

The silo is for cement storage. It comes in a dry bulk tank truck, and is pnematically conveyed into the silo.

The truck pulls into the batch plant, empty. The different sized aggregate is dropped into the truck, by weight, along with the powdered cement, and water is added. Some of the aggregate has to go in first, then the cement, then the water. Adding the cement first causes it clump up.

Old style plants used big levers, like a switching tower. Aggregate was dropped into the weighing bin, then dropped into the truck. Most old style (manualy operated) could batch out as much as 3 cu. yds at a time.

New, computer operated plants drop the correct amount of ingredients into the truck, along with the right amount of water.

The plant operator sets everything up according to how many cu. yrds. the order calls for. Todays trucks usually carry 9 cu. yrds. At least that’s what they licenses them for.

The truck is in a fast mixing mode while under the batch plant. Oncebatched, the truck pulls out from under the plant, and slows the mixing process down, to just a slow turn, as the driver heads to the job site.

I’ve operated an old manual style plant, and it’s a job! I have never operated todays modern batch plant.

The Walthers model could easily be made a modern plant, by adding a control/operators tower structure to the plant. The manual plants, you went up a stair way to a plateform, near the top, where the control levers and weighing bins were located.

Mike.

3

Thanks Mike. I remember discussing something like this before but forgot the sequence.

So the dry cement would be stored in larger silos nearby and pneumatically transfered to the silo in the RM plant. Underground piping on this Walthers model. Just wondering if this plant is big enough to require cement hopper rail service or if the supply would be handled by truck.

do you have any pics of a more modern facility with the operators tower? I wouldn’t know what it would look like.

4

As Mike said, pretty much just Cement, Aggregate, and Water.

Some decorative concrete will have special ingredients, and there is a little difference if the concrete will be used for pre-stressed castings, but for our model world purposes, those three ingredients are all you need to model.

-Kevin

5

I don’t know of any redi mix facilities that would get the powder from a railcar, it’s usually trucked in, from a storage facility, or even a transloading facility, where the truck could load right off the rail car, than deliver to the redi mix plant.

You could make your redi mix company part of a big cement supply facility that would receive it by rail.

I think Walthers had a kit for that, too.

The old plant I worked was just a stand alone batch plant, as I described earlier.

The newer plants have the operators area in a building that can be attached to the plant, or seperate. The one I’m most familiar with, the operators office is on the second floor of a garage/repair building, that is right next to the plant. He has a good view of the plant, and the truck as it enters, along with monitor screens he can view, of the area. All the gates and valves are controlled by electric relays, and not the levers, like the old plants.

Portable type plants, like what road builders use, the operator is in an office trailer, close to the plant.

Just about any type of building you can come up with could be the plant operators office. It doesn’t have to be a tower.

As far as the aggregate part of it all, it’s common now for the conveyor to be covered, and come from a covered loading area, where the front end loader fills the different hoppers, especially up here in the northern states.

For winter operations, the bins up in the plant have steam lines, so the aggregate can get heated, and hot water is used for mixing.

If you search for concrete batch plants, you’ll get lots of images, big and small. I don’t have any pictures that I have taken personally.

Mike.

6

Of the dozen or so concrete plants down here I am familiar with, none of them receive cement by railcar, only two receive aggregate from railcar.

There is a small facility in North Fort Myers where aggregate is off-loaded from railcars into trucks, but more frequently it is trucked in directly from the local llimestone quarries.

I don’t know where the cement originates from, but given the volume of dry powder trailers on Interstate-75, I would assume it is near Tampa.

-Kevin

7

There is a large concrete fabricator near me that makes large concrete pipes for sewer systems and sections for bridges etc. They have a cement storage onsite facility not unlike Medusa Cement kit and a Redi Mix plant onsite for general sale of concrete. That was the kind of company I was thinking of.

8

Back when I worked for the Ohio Highway Department back in the 60’s the 4 projects I worked on had concrete supplied by one plant located at the SE Johnson quarry operated by Kulhman Concrete Corp.

The plant was a large one and the stone was supplied by the quarry, sand was received by covered hopper from Wolcottville, IN on the N&W (Wabash). For Highway work both the sand and stone had separate piles as they were tested and kept separate from the other user’s piles. Cement was trucked in from the Port of Toledo, which received cement by lake freighter on the waterfront.

In addition to the water, cement, and aggregate a few admixtures were added as necessary. The most important was the air entraining agent which cuased small bubbles to be in the concrete mixture which strengthened final set up mixture. For bridge decks a retarder was added which lengthened the time the concrete would set up so the concrete finishers could get the best final finish. Sometimes colored dye would be added like red to show the concrete was being used around electrical lines buried in the ground. Also, during the winter we would use hot water to mix the concrete.

A story regarding the retarder, while we were in the midst of pouring a deck bridge which was about 30" deep with no steel beams underneath the retarder was changed. The original retarder was measured in quarts before adding to the batch, the new stuff was super concentrated and only required a couple of ounces, but they added it same as the old. Needless to say it took about 6 months before the concrete was hard enough to drive on.

Although the ready-mix trucks could haul 9 cubic yards of concrete, they were only usually carried a maximum of 8 cubic yards as they would be overloaded per the Highway Overweight specifications. We also found out if the wheelbase was too short that the trucks would be overweight with only 6 cubic yards on the truck. Several trucks were re-designed after that determination was made.</

9

Another additive used extensively today is flyash, along with superplastizers, which makes the concrete seem “wetter”.

Flyash is a powder, with a seperat bin to store it, and the plastiziers is a liguid, stored in 500 gal tanks. Smaller plants used 230 gal. fuel oil tanks.

You can reduce the amount of cement and replace it with up to 15% ( for walls 10% for finished slabs) flyash. All of these additives require their own storage bins or tanks.

Flyash is a byproduct of coal fired power plants, and used to be free, just had to pay for the trucking. I don’t know how they charge for it now days.

Mike.

10

For ODOT work fly ash was no allowed and we also required a 3" slump or less for incorporating into structures or pavement.

Rick Jesionowski

11

Same down here. The trucks usually run 1-2 yards under cubic capacity for weight compliance.

-Kevin

12

Plants up here in WI run with, and are licensed for 9 yrds., but many of the trucks, especially the front dischage, have 4 axles, 2 of which can be dropped down. And for traveling in neighboring IL., another axle is hanging on the rear. Not all have that, only those that operate in both states.

A front discharge truck stuffed full will hold 12 yrds.

OK then! [swg]

Anyway, I have some cement operations on my layout, using a transloading yard.

Cement arrives in hoppers, and the load is transferred to dry bulk trucks, then to outlying redi-mix operations.

I wanted to add a plant and storage, but it would take up too much room for my small layout.

Not all dry bulk trucks can load from a railcar unless they are equiped for it. I’m scratch building a stand alone portable transfer vacuum pump, for trucks that are not equiped for loading.

The dry bulk trucks you see on the road, with the extra vertical tank on the back, can load themselves.

Have fun designing and setting up your concrete operations!

Mike.

13

The information has been helpful. The plan was to always model the cement storage and distribution silos, aka Medusa Cement type structure, for accepting cement loads by rail.

The question was to whether or not to include the sidebar redi mix building as an additional source of rail traffic. It doesn’t seem worth the space for what little traffic would be generated (I’m not interested in aggregate traffic).

14

Concrete companies down here have sporadically tried the front discharge higher capacity mixer configurations.

I do not have any understanding of the ins-and-outs, but apparently a smaller three axle rear discharge mixer is more suitable for our market’s needs.

-Kevin

15

In Chicago you had the extra step (and still do in the modern plants there) of remembering to toggle or push the button under your desk that artificially inflates the batch weights for every load on the truck tickets so you can overcharge your customers.

16

[(-D] Hey, the material piles were wet, co’mon, can’t a guy make a buck? [(-D]

Mike.

17

Ha, indeed.

Although this (below) wasn’t concrete, this is exactly what Palumbo did with HMA. Got them prison time.

https://www.chicagotribune.com/news/ct-xpm-1996-10-04-9610080003-story.html

Additionally, one of my previous contractors in Chicagoland (not Palumbo) ended up being indicted, with several people, including the owner, going to Federal prison for (…wait for it…) …cheating the laborer union out of dues, then falsifying payroll numbers to cover it up, then lying to the FBI about it, not once, but TWICE. They got caught the first time and then committed other crimes in order to give the appearance of following the first court order. The second time around they committed wire fraud by using the US mail to send forged certified payrolls. Can’t make this stuff up [%-)]

https://www.justice.gov/usao-ndil/file/852251/download

18

I think this may depend on time, and perhaps on scope, of what the redi-mix plant serves.

In ‘older days’ it might have been more cost-effective to have some of the batch ingredients arrive by rail, even though the trucks have to be dispatched by road. I know of several of these plants in areas with bridge restrictions that would likely preclude large bulk truck deliveries – yours might be one such.

Likewise, for very large jobs – highway construction being an example – the necessary plants may be used on a scale that calls for multiple bulk delivery, but the ability to ‘store’ the bulk material for some period of time without having to transfer it to storage silos or leave it in piles. One of my great regrets is that, apparently, Alco cab units regularly ran up the EL Northern Branch with ‘concrete’ material supply trains to where 80/95 was being constructed across Englewood, only a couple of miles south of where I lived … and I had no idea until long after the show was over. So I have no idea how they actually did it.

19

What prompted the thread was my memory of this facility that I used to drive by occasionally. A redi mix plant/company that has been located there for over 25 years. Not a mobile batch plant. Looks much like the Walthers model. It is located on a rail line, but it never received rail service AFAIK. The small silos appear to hold the dry cement, and look too small to warrant rail service, just like the Walthers model. (So I guess the Wathers

20

Our SIL’s parents live in Fishers. That looks like a good size operation. They probably have their own dry bulk trucks for the powder.

You can see how the material bins are all enclosed. I did a 360 on Google satellite.

Front discharge trucks is about all you see in WI. If a company has rear discharge, they usually use them for back up.

With the front discharge, the driver (depending on his skills) together with the reach and ease of operation of the truck, is like another crew on the job.

The rear discharge, you need a guy to push the chute back and forth, so the driver can stay in the cab. If it’s just dumping into a pump, or a bucket ( and crane), the rear discharge are fine.

The batch office would up those stairs.

Good luck with your project.

Mike.