Quotulatiousness

March 23, 2024

The Roman Army’s Biggest Building Projects

toldinstone
Published Dec 15, 2023

The greatest achievements of the Roman military engineers.

Chapters:
0:00 Introduction
0:38 Marching camps
1:36 Bridges
2:40 Siegeworks
3:26 PIA VPN
4:32 Permanent forts
5:49 Roads
6:24 Frontier defenses
7:41 Canals
8:21 Civilian projects
8:54 The aqueduct of Saldae
(more…)

March 11, 2024

Why Railroads Don’t Need Expansion Joints

Filed under: Railways — Tags: — Nicholas @ 02:00

Practical Engineering
Published Dec 5, 2023

A friendly overview of thermal effects on railways.

Errata: At 9:00, the left column of calculations is incorrectly labeled “SI.” It should be imperial. Whoops!

Just as all materials have a mostly linear relationship between temperature change and length change, all materials also have a similar relationship between stress and change in length (often called strain). And this is part of the secret to continuous welded rail: restrained thermal expansion. You can overcome one with the other.
(more…)

March 2, 2024

QotD: Early siege warfare

Now the besieger’s side of the equation may seem like an odd place to start a primer on fortifications, but it actually makes a fair bit of sense, because the capabilities of a potential attacker is where most thinking about fortification begins. Siegecraft, both offensive and defensive, is a case of “antagonistic co-evolution“, a form of evolution through opposition where each side of the relationship evolves new features in response to the other: neither offensive siege techniques nor fortifications evolve in isolation but rather in response to each other.

In many ways the choice of where to begin following that process of evolution is arbitrary. We could in theory start anywhere from the very distant past or only very recently, but in this case I think it makes sense to begin with the early Near Eastern iron age because of the nature of our evidence. While it is clear that siege warfare must have been an important part of not only bronze age warfare but even pre-bronze age warfare, sources for the details of its practice in that era are sparse (in part because, as we’ll see, siege warfare was a sort of job done by lower status soldiers who often didn’t figure much into artwork focused on royal self-representation and legitimacy-building).

But as we move into the iron age, the dominant power that emerges in the Near East is the (Neo-)Assyrian Empire, the rulers of which make a point of foregrounding their siegecraft as part of a broader program of discouraging revolt by stressing the fearsome abilities of the Assyrian army (which in turn had much of its strength in its professional infantry). Consequently, we have some very useful artistic depictions of the Assyrian army doing siege work and at the same time some incomplete but still very useful information about the structure of the army itself. Moreover, it is just as the Assyrian Empire’s day is coming to a close (collapse in 609) that the surviving source base begins to grow markedly more robust (particularly, but not exclusively, in Greece), giving us dense descriptions of siege work (and even some manuals concerning it) in the following centuries, which we can in turn bring to the Assyrian evidence to better understand it. So this is a good place to start because it is the earliest point where we are really on firm ground in terms of understanding siegecraft in some detail. This does mean we are starting in medias res, with sophisticated states already using complex armies to assault fairly complex, sophisticated fortifications, which is worth keeping in mind.

That said, it should be noted that this is hardly beginning at the beginning. The earliest fortifications in most regions of the world were wooden and probably very simple (often just a palisade with perhaps an elevated watch-post), but by the late 8th century, well-defended sites (like walled cities) already sported sophisticated systems of stone walls and towers for defense. That caveat is in turn necessary because siegecraft didn’t evolve the same way everywhere: precisely because this is a system of antagonistic co-evolution it means that in places where either offensive or defensive methods (or technologies) took a different turn, one can end up with very different results down the line (something we’ll see especially with gunpowder).

Bret Devereaux, “Collections: Fortification, Part I: The Besieger’s Playbook”, A Collection of Unmitigated Pedantry, 2021-10-29.

January 26, 2024

Which Is Easier To Pull? (Railcars vs. Road Cars)

Filed under: Economics, Railways, USA — Tags: , — Nicholas @ 02:00

Practical Engineering
Published Nov 7, 2023

A lot of the engineering decisions that get made in railroading have to do with energy. How does the rolling resistance of a 20-ton freight railcar compare to my little grocery hauler?
(more…)

January 7, 2024

Every Type of Railcar Explained in 15 Minutes

Filed under: Cancon, Railways, USA — Tags: , , — Nicholas @ 02:00

Practical Engineering
Published 19 Sept 2023

How many of these cars have you spotted before?

Trains are one of the most fascinating engineered systems in the world, and they’re out there, right in the open for anyone to have a look! Once you start paying attention, it’s pretty satisfying to look for all the different types of railcars that show up on the tracks.
(more…)

January 1, 2024

The largest telescope that will ever be built*

Filed under: Americas, Science, Space, Technology — Tags: , , — Nicholas @ 02:00

Tom Scott
Published 2 Oct 2023

The asterisk is important.
β–  More on the ELT: @ESOobservatory https://eso.org

The Extremely Large Telescope, in Paranal, Chile, is probably going to be the largest optical telescope that will ever be constructed. I was invited out there by the UK Science and Technology Facilities Council and the European Southern Observatory, and I wasn’t going to turn down a chance like that.

πŸ“° DISCLAIMER
While the STFC and ESO invited me and arranged the logistics after arrival into the Antofagasta region, I was not paid for this (not even my travel costs) and I have sole editorial control over the video. This is not an advert.
(more…)

December 30, 2023

Building the Walls of Constantinople

Filed under: Europe, History, Military, Weapons — Tags: , , , , — Nicholas @ 02:00

toldinstone
Published 15 Sept 2023

This video, shot on location in Istanbul, explores the walls of Byzantine Constantinople — and describes how they finally fell to the Ottoman Turks in 1453.
(more…)

December 16, 2023

Do Droughts Make Floods Worse?

Filed under: Environment — Tags: , , , — Nicholas @ 02:00

Practical Engineering
Published 5 Sept 2023

The answer isn’t as simple as you might think!

One statistician famously said, “All models are wrong, but some are useful”. And even something as simple as the flow of water into the soil has so many complexities to keep track of. Like most answers to simple questions in engineering and in life: the answer is that it’s complicated.
(more…)

December 3, 2023

Every Construction Machine Explained in 15 Minutes

Filed under: Technology, USA — Tags: — Nicholas @ 02:00

Practical Engineering
Published 15 Aug 2023

A very quick overview of nearly every machine you’ll see on a construction site.

It takes a lot of big tools to build the roads, dams, sewage lift stations, and every other part of the constructed environment. To me, there’s almost nothing more fun than watching something get built, and that’s made all the better when you know what all those machines do.
(more…)

November 2, 2023

Keeping Clean in Rome

Filed under: Architecture, Europe, Health, History, Technology — Tags: , , , , , — Nicholas @ 02:00

seangabb
Published 2 Jul 2023

A lecture, given in June 2023, about bathing and keeping clean in the Roman World — plus an overview of depilation and going to the toilet.
(more…)

September 16, 2023

QotD: The Persian “Royal Roads”

The first thing worth clearing up about the Roman roads is that, contrary to a lot of popular belief, the Roman roads were not the first of their kind. And I mean that in a variety of ways: the construction of roadways with a solid, impermeable surface (that is, not just clearing and packing dirt) was not new with the Romans, but more importantly the concept of knitting together an empire with a system of roadways was not new.

The oldest road network that we have pretty good evidence for was the Persian Royal Road of the Achaemenids but these too were not the first (the Achaemenid dynasty ruling a vast empire from 559 to 330 BC; this is the Persian Empire of Xerxes and Darius III). Even before them the Assyrians (Middle and Neo-Assyrian Empires running from 1363 to 609 BC)1 had build roadways to hold together parts of their empire, though I confess I know very little of the extent of that road system except that we’re fairly sure it existed and like the later systems we’re going to talk about, it included not just the physical infrastructure of the roads but a sophisticated relay system to allow official messengers to move very rapidly over the network.

The modern perception of the Persian Royal Road is conditioned perhaps a bit too much by Herodotus who described the royal road – singular – as a single highway running from Susa to Sardis. Susa was one of several Achaemenid royal capitals and it sat at the edge of the Iranian plateau where it meets the lowland valley of Mesopotamia, essentially sitting right on the edge where the Persian “heartland” met the area of imperial conquests. Meanwhile, Sardis was the westernmost major Achaemenid administrative center, the regional capital, as it were, for Anatolia and the Aegean. So you can see the logic of that being an important route, but the road system was much larger. Indeed, here is a very rough sketch of how we might understand the whole system.

Compare the dashed line – the Royal Road as described by Herodotus – with the solid lines, the rest of the system we can glean from other sources or from archaeology and you can see that Herodotus hasn’t given us the whole story. For what it is worth, I don’t think Herodotus here is trying to lie – he has just described the largest and most important trunk road that leads to his part of the world.

This system doubtlessly emerged over time. Substantial parts of the road network almost certainly predated the Achaemenids and at least some elements were in place under the first two Achaemenid Great Kings (Cyrus II, r. 559-530 and Cambyses II, r. 530-22) but it seems clear that it is the third Achaemenid ruler, Darius I (r. 522-486; this is the fellow who dispatched the expedition defeated at Marathon, but his reign was far more important than that – he is the great organizer of the Persian Empire) who was responsible for the organization, formalization and expansion of the system. And in practice we can split that system into two parts, the physical infrastructure of roads and then the relay system built atop that system.

In terms of the physical infrastructure, as far as I can tell, the quality of Persian Royal Roads varied a lot. In some areas where the terrain was difficult, we see sections of road cut into the rock or built via causeways over ravines. Some areas were paved, but most – even most of the “royal” roads (as distinct from ancillary travel routes) were not.2 That said, maintenance seems to have been more regular on the royal roads, meaning they would be restored more rapidly after things like heavy rains that might wash an unpaved road out, making them more reliable transport routes for everyone. They also seem to have been quite a bit wider; Achaemenid armies could have long logistics tails and these roads had to accommodate those. Several excavated sections of royal roads are around 5m wide, but we ought to expect a lot of variation.

On top of the physical infrastructure, there was also a system of way-stations and stopover points along the road. These were not amenities for everyone but rather a system for moving state officials, messengers, soldiers, and property (like taxes). While anyone could, presumably, walk down the road, official travelers carried a sealed travel authorization issued by either a satrap (the Persian provincial governors) or the king himself. Such authorizations declared how many travelers there were, where they were going and what the way-stations, which stocked supplies, should give them. Of course that in turn meant that local satraps had to make sure that way-stations remained stocked up with food, fodder for animals, spare horses and so on. Fast messengers could also be sent who, with that same authorization, would change horses at each way-station, allowing them to move extremely fast over the system, with one estimate suggesting that a crucial message could make the trip from Sardis to Susa – a trip of approximately 2,500km (1,550 miles, give or take) in twelve days (by exchanging not only horses, but riders, as it moved).

All of which gives some pretty important clues to why royal roads were set up and maintained. Notice how the system specifically links together key administrative hubs, like the three main Achaemenid capitals (Susa, Ekbatana and Persepolis) and key administrative centers (Memphis, Sardis, Babylon, etc.) and that while anyone can use the roads, the roads serve as the basis for a system to handle the logistics of moving officials and state messages, which of course could also serve as the basis for moving armies. After all, you can send messengers down the royal roads, through the existing system set up for them, to instruct your satraps to gather local forces or more importantly to gather local food supplies and move them to the road in depots where the army can pick them up (and perhaps some local troops) as it moves through to a nearby trouble spot (while the nice, wide road allows you to bring lots of pack animals and carts with your army).

In short this is a large, expensive but effective system for managing the problem of distance in a large empire. Cutting down travel and message times reduces the independence of the satraps, allowing the Great King to keep an eye on them, while the roads provide the means to swiftly move armies from the core of the empire out to the periphery. We can actually see this play out with Alexander’s invasion. He crosses into Asia in 334 and defeats the local satrapal army at Granicus in 334. Moving into the Levant in 333, he’s met at Issus by Darius III with a massive army, collected from the central and western parts of the empire – which means that news of Alexander’s coming has reached Darius who has then marshaled all of those troops from his satrapies (and hired some mercenaries), presumably using his efficient message system to do it and then moved that force down the road system to meet Alexander. Alexander defeats that army, but is met by another huge army at Gaugamela in 331, this time gathered mostly from the eastern parts of the empire. While the Persian army fails in defeating Alexander, the exercise shows the power of the system in allowing the Great King, Darius III to coordinate the military efforts of an enormous empire.

So this is a system meant to enable the imperial center to control its periphery by enabling the court to keep tabs on the satraps, to get messages to and from them and move armies and officials (and taxes!) around. And doubtless it was also not lost on anyone that such a visible series of public works – even if the roads were not always paved and had to be repaired after heavy rains and such – was also an exercise in legitimacy building, both a visual demonstration of the Great King’s power and resources but also a display of his generosity and industry.

And I lead with all of that because the Roman road network works the same way, just on an even larger scale. Which isn’t to say the Romans were copying the Achaemenids (they don’t seem to have been) but rather that this is a common response to the problem of managing an uncommonly large empire.

Bret Devereaux, “Collections: Roman Roads”, A Collection of Unmitigated Pedantry, 2023-06-02.


    1. The Middle Assyrian Empire and the Neo-Assyrian or New Assyrian Empires were, in fact, the same state. We split them up because of a severe contraction in Assyrian power during the Late Bronze Age Collapse.

    2. On this, see Henkelman and Jacobs, 727-8

July 25, 2023

WWI Footage: Narrow Gauge Train Lines in France

Filed under: France, History, Military, Railways, USA, WW1 — Tags: , , — Nicholas @ 02:00

Charlie Dean Archives
Published 14 Aug 2013

American forces constructing railways throughout France to help move men and supplies during World War One. We see US Army personnel laying the sleepers and track for the extensive network of two foot (60cm) narrow gauge lines, ballasting work, loading and laying of pre-built trackwork. We also see scenes of the railway in action as the little trains trundle along country lanes and through the town streets. The film ends with scenes of the train taking soldiers towards the front lines.

After the war the lines were abandoned and most of the locomotives and rollingstock simply left where they were last used, with many being salvaged by the locals to help with logging activities.

CharlieDeanArchives – Archive footage from the 20th century making history come alive!

(more…)

July 11, 2023

What is a HUMP Yard?

Filed under: Business, History, Railways, USA — Tags: , — Nicholas @ 02:00

V12 Productions
Published 24 Oct 2022

Hump yards are amazing pieces of engineering that allow railroads to use gravity to sort cars and build trains. Of course, not all railroad equipment can be humped.
(more…)

July 5, 2023

Why Engineers Can’t Control Rivers

Filed under: Environment, Technology, USA — Tags: , , , — Nicholas @ 02:00

Practical Engineering
Published 4 Apr 2023

πŸ’§ The unintended consequences of trying to change the course of rivers
(more…)

July 3, 2023

Three Forgotten Roman Megaprojects

Filed under: Europe, History, Italy, Military — Tags: , , , , — Nicholas @ 02:00

toldinstone
Published 31 Mar 2023

The longest tunnel in ancient history. A highway suspended over a raging river. A secret harbor for the Roman navy. These are three of the most impressive Roman engineering projects that you’ve probably never heard of.
(more…)

Older Posts »

Powered by WordPress