3:15 a.m.
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