Page 1 of 1

Roman Roads

Posted: Tue Sep 04, 2007 6:23 am
by Digit
In between tree felling and resting, (these cancer treatments tire you out) I've been watching a programme about how the Romans laid out and constructed roads, viaducts etc using bob weights to establish a base line.
As an engineer I fully understand the principles, but, how do you aim a road at a fort, township, river crossing etc that is beyond the horizon and you can't see?

Posted: Tue Sep 04, 2007 10:20 am
by Minimalist
http://www.highwayengineers.org/scanner_summer03j.html
Although Roman surveyors were extremely skilled and could lay out accurate curves, Roman roadways typically are linear. This was due to the use of sighting techniques, which naturally resulted in very long tangents. This is most noticeable in the fact that Roman roads make most of their key turns and deflections on high ground where sighting was most easily facilitated. Road segments would often be laid out with series of hundreds of sighting points and beacons.

Posted: Tue Sep 04, 2007 11:03 am
by Digit
[/quote]http://www.romans-in-britain.org.uk/map ... .htm[quote]
If you take a look at this map Min you can see that some of the roads are arrow straight, others less so. In some cases terrain made a straight road impossible of course, but some of the curves seem to be as a result of their aiming 'off' and a correction being necessary.
With enough trial and error a dead straight course is acheivable, but I have a gut feeling that the Romans were better than that.

Posted: Tue Sep 04, 2007 11:45 am
by Minimalist
Well, in answer to your original question I wonder if it isn't a chicken and egg thing.

The roads were build to serve a primarily military purpose: How to move the legions quickly from one place to another. The utilization by commercial interests and other travellers came after the armies had moved on. So, perhaps the towns grew up at the bridges. In fact, lots of towns grew up near Roman military camps....still noted in Britain by the repeated use of the word "chester" (L. "castra") in your place names.

Posted: Tue Sep 04, 2007 12:10 pm
by Digit
Or as Monty Python asked, 'apart from roads what did the Romans ever do for us?'

Posted: Tue Sep 04, 2007 2:06 pm
by Minimalist
"Brought peace?"

"Oh, PEACE!....Fuck off!!!!"

Re: Roman Roads

Posted: Tue Sep 04, 2007 6:37 pm
by john
Digit wrote:In between tree felling and resting, (these cancer treatments tire you out) I've been watching a programme about how the Romans laid out and constructed roads, viaducts etc using bob weights to establish a base line.
As an engineer I fully understand the principles, but, how do you aim a road at a fort, township, river crossing etc that is beyond the horizon and you can't see?

Although its been decades since I regularly read Latin, I have a vague memory - probably from the dread Julius Caesar's "All Gaul is Divided into Three Parts" - that the Romans were one of the earliest peoples to actually survey a roadway, or a good portion of it - end to end - before building it. This would have been mostly on foot, and an interesting early example of reverse engineering. Find the only river crossing worth a shit within a hundred miles and lay out the easiest road to it. River and hill/mountain crossings, any difficult terrain, in short, would have been scouted for the most economically constructed roadway. This has the windfall of also probably being the most energy efficient path to move large amounts of people/goods. The Romans were pretty damn good at this kind of economics, and note that I say economics, because the other point about the Romans is that they consistently used "science" as a method to improve the economy of the empire. The personal lives of the ruling class were an exception, of course, as is amply demonstrated right up to the present.........but that's another subject.

Ok. Trivia question for the day, which most, if not all of you, already know, is:

"What do the Romans and British narrow gauge railways have in common?



john

Posted: Tue Sep 04, 2007 6:47 pm
by Beagle
I know the answer to that trivia question john. I'll pass though and let someone else take a crack at it. I'm sure others know it, but if for some strange reason it isn't correctly answered by tomorrow evening I'll spill the beans.

Posted: Tue Sep 04, 2007 8:55 pm
by Minimalist
It is true that the Via Appia (312 BC) ran straight as an arrow from Rome's southern gate to Terracina. This route took the Romans down the Alban Hills and across the Pontine Marshes. They made no effort to go around these obstacles.

Stubborn? Or perhaps just understanding that as the road was built for a military purpose that it was necessary for the troops to get there by the most direct route possible.

Posted: Tue Sep 04, 2007 9:17 pm
by Beagle
I'm sure that's not the answer john is looking for.

Posted: Tue Sep 04, 2007 11:00 pm
by Minimalist
That one has kind of been debunked anyway.

http://www.snopes.com/history/american/gauge.htm

Posted: Wed Sep 05, 2007 3:41 am
by Digit
Sorry Min but that's not true either! The standard guage in the UK, and inherited in part by yourselves, was five feet!
As designed, the locos and rolling stock had their wheel flanges on the outside of the rails. On bends the inner wheel would occasionally lift clear of the rail, so they rebuilt everything with the flanges on the inside of the trackway.
Problem solved!
But your five foot guage is now four feet eight and a half inches.

Posted: Wed Sep 05, 2007 5:05 am
by Beagle
That one has kind of been debunked anyway.
Debunked or not Min - that's the answer.

Posted: Wed Sep 05, 2007 9:21 pm
by john
Beagle wrote:
That one has kind of been debunked anyway.
Debunked or not Min - that's the answer.

I've seen no other plausible argument for the decision to run rails at a width of approx. 4' 8" at later dates. Perhaps you have documentation?

john

Posted: Wed Sep 05, 2007 9:30 pm
by Minimalist
Snopes has already invested far more time into this issue than is necessary.