Hi Nathan,
On 2020-06-09 7:21 p.m., Natfoot wrote:
Hi Michael, After reading through this further, I could make the counter argument that modern systems like (ETCS Level 2, LZB) include cab signalling where signals along the line are not necessary and everything is shown on a display in the engine does not meet the very On The Ground Rule of OpenStreetMap. To map this information you will need additional knowledge to identify the technology through government or company documents to make a correct assessment on the specific system in use.
How is this different from what I am suggesting?
ETCS systems have Eurobalises/Euroloops on the track for odometry and other messages, and LZB has cable loops. These are both visible on the ground. PTC and rules are not.
If we can both assume that we both have extensive working knowledge of railroads or railways and that we can identify correctly the system in use. Can we assume that we should be allowed to map it if we can look at the ground and see that it is what it is? Or do we need to make the assumption that we don't have a working knowledge of railroads or railways and that we need to assume a role as an outsider when mapping railroads and only map what we can see (signals, switches, balises, magnets, contacts etc.*)*?
I think this is where we need to separate the discussion between rules and train protection. Taking the ETCS example, one can affirmatively assert that a railway line is ETCS-equipped by pointing out Eurobalises/Euroloops. Similarly in the US, one can affirmatively assert that a line is ACSES-equipped by pointing out its balises.
Operating rules are not train protection systems. Using the same two examples, I couldn't tell by looking at what's on the ground whether an ETCS-equipped railway line is operating in Level 1, 2, or 3. Similarly, I couldn't tell by looking at what's on the ground whether a North American railway line is OCS or Rule 105/non-main track (or indeed whether it is PTC-equipped in the US).
In _some_ circumstances, one may be able to tell where CTC or OCS territory begins and/or ends. While signs for these exist (in some locations), they are not properties of the railway line itself: rather, they are properties of how movements on the railway line are conducted.
For example, consider the difference between OCS+ABS and CTC. By simply observing the railway in situ, could you tell the difference between the two? (And the signs don't count, because they could simply be overridden in Special Instructions (or the US equivalent). Moreover, there are no signs that differentiate -- for example -- siding control territory (SCT) from CTC sidings in Canada.)
While I could *maybe* see a future schema where things like cautionary limits, yard limits, CTC/OCS limits, station name signs etc. are defined, they certainly don't fall under the existing train protection schema.
This discussion appears to skirt around the On The Ground Rule of OpenStreetMap.
While we're talking about skirting the rule, I find it peculiar that ITCS is included in the train protection systems schema, since (AFAIK) its main selling point is that it has no trackside infrastructure. Surely if we're going for a consistent "on the ground" approach, we should remove this, no?
(I've been following the project and mailing list for a while but can't seem to recall this being discussed recently, and haven't found anything in the archives.)
Cheers, --Tyson