In my experience -

The FRA retains the right to enforce safety on any rail operation in the United States under the broad definition of their authority. There are some operations such as some mining operations that fall under MSHA instead. It could get ridiculous if the FRA showed up to inspect every trackmobile, amusement park or live steam operation.

The FRA has chosen (for now) to exempt certain operations that meet the definition of "insular". An insular operation:

1. Does not have common carrier authority.
2. Does not have a common carrier operating over it - with an exception to allow the interchange of cars with a minimum of joint operations. Track safety standards still apply to privately owned track that has a common carrier operating onit such as industrial track.
3. Is not a part of the general railroad system.
4. Does not cross a public highway, navigable waterway or another railroad, and does not parallel another railroad's track closer than 30 feet.

A tourist railroad or industry that is insular does not typically fall under FRA authority. Most amusement park railroads, being insular, will fall under the state inspector, as will most light rail transit oeprations.

If a non-common carrier operation is not insular (such as a tourist railroad that crosses a public road) but operates over a common carrier, typically they fall under full FRA jurisdiction. On a non-insular operation that does not operate over a common carrier, the FRA will typically only apply and enforce some of its regulations - typically track safety standards (but there are no standards for narrow gauge), steam locomotive inspection, accident and injury reporting, hours of service and crossing signals. THis assumes that the oepration has some sort of training and qualification program, and otherwise generally is a safe and sane operation.

So a tourist railroad might be full FRA, FRA "light" or insular - all depending upon circumstances. After many years, the FRA decided to exert its authority over the Georgetown Loop - because their lower road entrance under the High Bridge was actually a public road.

Don't belive me - read it for yourself. It is in Appendix A of 49 CFR 209.

THE EXTENT AND EXERCISE OF FRA’S SAFETY
JURISDICTION
The Safety Act and, as amended by the
RSIA, the older safety statutes apply to
‘‘railroads.’’ Section 202(e) of the Safety Act
defines railroad as follows:
The term ‘‘railroad’’ as used in this title
means all forms of non-highway ground
transportation that run on rails or electromagnetic
guideways, including (1) commuter
or other short-haul rail passenger service in
a metropolitan or suburban area, as well as
any commuter rail service which was operated
by the Consolidated Rail Corporation as
of January 1, 1979, and (2) high speed ground
transportation systems that connect metropolitan
areas, without regard to whether
they use new technologies not associated
with traditional railroads. Such term does
not include rapid transit operations within
an urban area that are not connected to the
general railroad system of transportation.

Prior to 1988, the older safety statutes had
applied only to common carriers engaged in
interstate or foreign commerce by rail. The
Safety Act, by contrast, was intended to
reach as far as the Commerce Clause of the
Constitution (i.e., to all railroads that affect
interstate commerce) rather than be limited
to common carriers actually engaged in
interstate commerce. In reporting out the
bill that became the 1970 Safety Act, the
House Committee on Interstate and Foreign
Commerce stated:
The Secretary’s authority to regulate extends
to all areas of railroad safety. This legislation
is intended to encompass all those
means of rail transportation as are commonly
included within the term. Thus,
‘‘railroad’’ is not limited to the confines of
‘‘common carrier by railroad’’ as that language
is defined in the Interstate Commerce
Act.
H.R. Rep. No. 91–1194, 91st Cong., 2d Sess. at
16 (1970).
FRA’s jurisdiction was bifurcated until, in
1988, the RSIA amended the older safety
statutes to make them coextensive with the
Safety Act by making them applicable to
railroads and incorporating the Safety Act’s
definition of the term (e.g.,45 U.S.C. 16, as
amended). The RSIA also made clear that
FRA’s safety jurisdiction is not confined to
entities using traditional railroad technology.
The new definition of ‘‘railroad’’ emphasized
that all non-highway high speed
ground transportation systems—regardless
of technology used—would be considered
railroads.
Thus, with the exception of self-contained
urban rapid transit systems, FRA’s statutory
jurisdiction extends to all entities that
can be construed as railroads by virtue of
their providing non-highway ground transportation
over rails or electromagnetic
guideways, and will extend to future railroads
using other technologies not yet in
use. For policy reasons, however, FRA does
not exercise jurisdiction under all of its regulations
to the full extent permitted by statute.
Based on its knowledge of where the
safety problems were occurring at the time
of its regulatory action and its assessment of
the practical limitations on its role, FRA
has, in each regulatory context, decided that
the best option was to regulate something
less than the total universe of railroads.
For example, all of FRA’s regulations exclude
from their reach railroads whose entire
operations are confined to an industrial installation
(i.e., ‘‘plant railroads’’), such as
those in steel mills that do not go beyond
the plant’s boundaries. E.g., 49 CFR
225.3(a)(1) (accident reporting regulations).
Some rules exclude passenger operations
that are not part of the general railroad system
(such as some tourist railroads) only if
they meet the definition of ‘‘insular.’’ E.g.,
49 CFR 225.3(a)(3) (accident reporting) and
234.3(c) (grade crossing signal safety). Other
regulations exclude not only plant railroads
but all other railroads that are not operated
as a part of, or over the lines of, the general
railroad system of transportation. E.g., 49
CFR 214.3 (railroad workplace safety).
By ‘‘general railroad system of transportation,’’
FRA refers to the network of standard
gage track over which goods may be
transported throughout the nation and passengers
may travel between cities and within
metropolitan and suburban areas. Much of
this network is interconnected, so that a rail
vehicle can travel across the nation without
leaving the system. However, mere physical
connection to the system does not bring
trackage within it. For example, trackage
within an industrial installation that is connected
to the network only by a switch for
the receipt of shipments over the system is
not a part of the system.
Moreover, portions of the network may
lack a physical connection but still be part
of the system by virtue of the nature of operations
that take place there. For example,
the Alaska Railroad is not physically connected
to the rest of the general system but
is part of it. The Alaska Railroad exchanges
freight cars with other railroads by car float
and exchanges passengers with interstate
carriers as part of the general flow of interstate
commerce. Similarly, an intercity high
speed rail system with its own right of way
would be part of the general system although
not physically connected to it. The presence
on a rail line of any of these types of railroad
operations is a sure indication that such
trackage is part of the general system: the
movement of freight cars in trains outside
the confines of an industrial installation, the
movement of intercity passenger trains, or
the movement of commuter trains within a
metropolitan or suburban area. Urban rapid
transit operations are ordinarily not part of
the general system, but may have sufficient
connections to that system to warrant exercise
of FRA’s jurisdiction (see discussion of
passenger operations, below). Tourist railroad
operations are not inherently part of
the general system and, unless operated over
the lines of that system, are subject to few of
FRA’s regulations.
The boundaries of the general system are
not static. For example, a portion of the system
may be purchased for the exclusive use
of a single private entity and all connections,
save perhaps a switch for receiving
shipments, severed. Depending on the nature
of the operations, this could remove that
portion from the general system. The system
may also grow, as with the establishment of
intercity service on a brand new line. However,
the same trackage cannot be both inside
and outside of the general system depending
upon the time of day. If trackage is
part of the general system, restricting a certain
type of traffic over that trackage to a
particular portion of the day does not change
the nature of the line—it remains the general
system.
Of course, even where a railroad operates
outside the general system, other railroads
that are definitely part of that system may
have occasion to enter the first railroad’s
property (e.g., a major railroad goes into a
chemical or auto plant to pick up or set out
cars). In such cases, the railroad that is part
of the general system remains part of that
system while inside the installation; thus,
all of its activities are covered by FRA’s regulations
during that period. The plant railroad
itself, however, does not get swept into
the general system by virtue of the other
railroad’s activity, except to the extent it is
liable, as the track owner, for the condition
of its track over which the other railroad operates
during its incursion into the plant. Of
course, in the opposite situation, where the
plant railroad itself operates beyond the
plant boundaries on the general system, it
becomes a railroad with respect to those particular
operations, during which its equipment,
crew, and practices would be subject
to FRA’s regulations.
In some cases, the plant railroad leases
track immediately adjacent to its plant from
the general system railroad. Assuming such
a lease provides for, and actual practice entails,
the exclusive use of that trackage by
the plant railroad and the general system
railroad for purposes of moving only cars
shipped to or from the plant, the lease would
remove the plant railroad’s operations on
that trackage from the general system for
purposes of FRA’s regulations, as it would
make that trackage part and parcel of the
industrial installation. (As explained above,
however, the track itself would have to meet
FRA’s standards if a general system railroad
operated over it. See 49 CFR 213.5 for the
rules on how an owner of track may assign
responsibility for it.) A lease or practice that
permitted other types of movements by general
system railroads on that trackage
would, of course, bring it back into the general
system, as would operations by the
plant railroad indicating it was moving cars
on such trackage for other than its own purposes
(e.g., moving cars to neighboring industries
for hire).
FRA exercises jurisdiction over tourist,
scenic, and excursion railroad operations
whether or not they are conducted on the
general railroad system. There are two exceptions:
(1) operations of less than 24-inch
gage (which, historically, have never been
considered railroads under the Federal railroad
safety laws); and (2) operations that are
off the general system and ‘‘insular’’ (defined
below).
Insularity is an issue only with regard to
tourist operations over trackage outside of
the general system used exclusively for such
operations. FRA considers a tourist operation
to be insular if its operations are limited
to a separate enclave in such a way that
there is no reasonable expectation that the
safety of any member of the public’except a
business guest, a licensee of the tourist operation
or an affiliated entity, or a
trespasser’would be affected by the operation.
A tourist operation will not be considered
insular if one or more of the following
exists on its line:
•A public highway-rail crossing that is in
use;
•An at-grade rail crossing that is in use;
•A bridge over a public road or waters used
for commercial navigation; or
•A common corridor with a railroad, i.e.,
its operations are within 30 feet of those of
any railroad.
When tourist operations are conducted on
the general system, FRA exercises jurisdiction
over them, and all of FRA’s pertinent
regulations apply to those operations unless
a waiver is granted or a rule specifically
excepts such operations (e.g., the passenger
equipment safety standards contain an exception
for these operations, 49 CFR
238.3(c)(3), even if conducted on the general
system). When a tourist operation is conducted
only on track used exclusively for
that purpose it is not part of the general system.
The fact that a tourist operation has a
switch that connects it to the general system
does not make the tourist operation
part of the general system if the tourist
trains do not enter the general system and
the general system railroad does not use the
tourist operation’s trackage for any purpose
other than delivering or picking up shipments
to or from the tourist operation itself.
If a tourist operation off the general system
is insular, FRA does not exercise jurisdiction
over it, and none of FRA’s rules
apply. If, however, such an operation is not
insular, FRA exercises jurisdiction over the
operation, and some of FRA’s rules (i.e.,
those that specifically apply beyond the general
system to such operations) will apply.
For example, FRA’s rules on accident reporting,
steam locomotives, and grade crossing
signals apply to these non-insular tourist operations
(see 49 CFR 225.3, 230.2 amd 234.3), as
do all of FRA’s procedural rules (49 CFR
parts 209, 211, and 216) and the Federal railroad
safety statutes themselves.
In drafting safety rules, FRA has a specific
obligation to consider financial, operational,
or other factors that may be unique to tourist
operations. 49 U.S.C. 20103(f). Accordingly,
FRA is careful to consider those factors
in determining whether any particular
rule will apply to tourist operations. Therefore,
although FRA asserts jurisdiction quite
broadly over these operations, we work to
ensure that the rules we issue are appropriate
to their somewhat special circumstances.

It is important to note that FRA’s exercise
of its regulatory authority on a given matter
does not preclude it from subsequently
amending its regulations on that subject to
bring in railroads originally excluded. More
important, the self-imposed restrictions on
FRA’s exercise of regulatory authority in no
way constrain its exercise of emergency
order authority under section 203 of the Safety
Act. That authority was designed to deal
with imminent hazards not dealt with by existing
regulations and/or so dangerous as to
require immediate, ex parte action on the
government’s part. Thus, a railroad excluded
from the reach of any of FRA’s regulations is
fully within the reach of FRA’s emergency
order authority, which is coextensive with
FRA’s statutory jurisdiction over all railroads.
FRA’S POLICY ON JURISDICTION OVER
PASSENGER OPERATIONS
Under the Federal railroad safety laws,
FRA has jurisdiction over all railroads except
‘‘rapid transit operations in an urban
area that are not connected to the general
railroad system of transportation.’’ 49 U.S.C.
20102. Within the limits imposed by this authority,
FRA exercises jurisdiction over all
railroad passenger operations, regardless of
the equipment they use, unless FRA has specifically
stated below an exception to its exercise
of jurisdiction for a particular type of
operation. This policy is stated in general
terms and does not change the reach of any
particular regulation under its applicability
section. That is, while FRA may generally
assert jurisdiction over a type of operation
here, a particular regulation may exclude
that kind of operation from its reach. Therefore,
this statement should be read in conjunction
with the applicability sections of
all of FRA’s regulations.
INTERCITY PASSENGER OPERATIONS
FRA exercises jurisdiction over all intercity
passenger operations. Because of the nature
of the service they provide, standard
gage intercity operations are all considered
part of the general railroad system, even if
not physically connected to other portions of
the system. Other intercity passenger operations
that are not standard gage (such as a
magnetic levitation system) are within
FRA’s jurisdiction even though not part of
the general system.
COMMUTER OPERATIONS
FRA exercises jurisdiction over all commuter
operations. Congress apparently intended
that FRA do so when it enacted the
Federal Railroad Safety Act of 1970, and
made that intention very clear in the 1982
and 1988 amendments to that act. FRA has
attempted to follow that mandate consistently.
A commuter system’s connection to
other railroads is not relevant under the rail
safety statutes. In fact, FRA considers commuter
railroads to be part of the general
railroad system regardless of such connections.
FRA will presume that an operation is a
commuter railroad if there is a statutory determination
that Congress considers a particular
service to be commuter rail. For example,
in the Northeast Rail Service Act of
1981, 45 U.S.C. 1104(3), Congress listed specific
commuter authorities. If that presumption
does not apply, and the operation does not
meet the description of a system that is presumptively
urban rapid transit (see below),
FRA will determine whether a system is
commuter or urban rapid transit by analyzing
all of the system’s pertinent facts.
FRA is likely to consider an operation to be
a commuter railroad if:
•The system serves an urban area, its suburbs,
and more distant outlying communities
in the greater metropolitan area,
•The system’s primary function is moving
passengers back and forth between their
places of employment in the city and their
homes within the greater metropolitan area,
and moving passengers from station to station
within the immediate urban area is, at
most, an incidental function, and
•The vast bulk of the system’s trains are
operated in the morning and evening peak
periods with few trains at other hours.
Examples of commuter railroads include
Metra and the Northern Indiana Commuter
Transportation District in the Chicago area;
Virginia Railway Express and MARC in the
Washington area; and Metro-North, the Long
Island Railroad, New Jersey Transit, and the
Port Authority Trans Hudson (PATH) in the
New York area.
OTHER SHORT HAUL PASSENGER SERVICE
The federal railroad safety statutes give
FRA authority over ‘‘commuter or other
short-haul railroad passenger service in a
metropolitan or suburban area.’’ 49 U.S.C.
20102. This means that, in addition to commuter
service, there are other short-haul
types of service that Congress intended that
FRA reach. For example, a passenger system
designed primarily to move intercity travelers
from a downtown area to an airport, or
from an airport to a resort area, would be
one that does not have the transportation of
commuters within a metropolitan area as its
primary purpose. FRA would ordinarily exercise
jurisdiction over such a system as
‘‘other short-haul service’’ unless it meets
the definition of urban rapid transit and is
not connected in a significant way to the
general system.
URBAN RAPID TRANSIT OPERATIONS
One type of short-haul passenger service
requires special treatment under the safety
statutes: ‘‘rapid transit operations in an
urban area.’’ Only these operations are excluded
from FRA’s jurisdiction, and only if
they are ‘‘not connected to the general railroad
system.’’ FRA will presume that an operation
is an urban rapid transit operation if
the system is not presumptively a commuter
railroad (see discussion above) the operation
is a subway or elevated operation with its
own track system on which no other railroad
may operate, has no highway-rail crossings
at grade, operates within an urban area, and
moves passengers from station to station
within the urban area as one of its major
functions.
Where neither the commuter railroad nor
urban rapid transit presumptions applies,
FRA will look at all of the facts pertinent to
a particular operation to determine its proper
characterization. FRA is likely to consider
an operation to be urban rapid transit
if:
•The operation serves an urban area (and
may also serve its suburbs),
•Moving passengers from station to station
within the urban boundaries is a major function
of the system and there are multiple
station stops within the city for that purpose
(such an operation could still have the transportation
of commuters as one of its major
functions without being considered a commuter
railroad), and
•The system provides frequent train service
even outside the morning and evening
peak periods.
Examples of urban rapid transit systems
include the Metro in the Washington, D.C.
area, CTA in Chicago, and the subway systems
in New York, Boston, and Philadelphia.
The type of equipment used by such a system
is not determinative of its status. However,
the kinds of vehicles ordinarily associated
with street railways, trolleys, subways, and
elevated railways are the types of vehicles
most often used for urban rapid transit operations.
FRA can exercise jurisdiction over a rapid
transit operation only if it is connected to
the general railroad system, but need not exercise
jurisdiction over every such operation
that is so connected. FRA is aware of several
different ways that rapid transit operations
can be connected to the general system. Our
policy on the exercise of jurisdiction will depend
upon the nature of the connection(s). In
general, a connection that involves operation
of transit equipment as a part of, or
over the lines of, the general system will
trigger FRA’s exercise of jurisdiction. Below,
we review some of the more common types of
connections and their effect on the agency’s
exercise of jurisdiction. This is not meant to
be an exhaustive list of connections.
RAPID TRANSIT CONNECTIONS SUFFICIENT TO
TRIGGER FRA’S EXERCISE OF JURISDICTION
Certain types of connections to the general
railroad system will cause FRA to exercise
jurisdiction over the rapid transit line to the
extent it is connected. FRA will exercise jurisdiction
over the portion of a rapid transit operation
that is conducted as a part of or over
the lines of the general system. For example,
rapid transit operations are conducted on
the lines of the general system where the
rapid transit operation and other railroad
use the same track. FRA will exercise its jurisdiction
over the operations conducted on
the general system. In situations involving
joint use of the same track, it does not matter
that the rapid transit operation occupies
the track only at times when the freight,
commuter, or intercity passenger railroad
that shares the track is not operating. While
such time separation could provide the basis
for waiver of certain of FRA’s rules (see 49
CFR part 211), it does not mean that FRA
will not exercise jurisdiction. However, FRA
will exercise jurisdiction over only the portions
of the rapid transit operation that are
conducted on the general system. For example,
a rapid transit line that operates over
the general system for a portion of its length
but has significant portions of street railway
that are not used by conventional railroads
would be subject to FRA’s rules only with respect
to the general system portion. The remaining
portions would not be subject to
FRA’s rules. If the non-general system portions
of the rapid transit line are considered
a ‘‘rail fixed guideway system’’ under 49 CFR
part 659, those rules, issued by the Federal
Transit Administration (FTA), would apply
to them.
Another connection to the general system
sufficient to warrant FRA’s exercise of jurisdiction
is a railroad crossing at grade where
the rapid transit operation and other railroad
cross each other’s tracks. In this situation,
FRA will exercise its jurisdiction sufficiently
to assure safe operations over the atgrade
railroad crossing. FRA will also exercise
jurisdiction to a limited extent over a
rapid transit operation that, while not operated
on the same tracks as the conventional
railroad, is connected to the general system
by virtue of operating in a shared right-ofway
involving joint control of trains. For example,
if a rapid transit line and freight railroad
were to operate over a movable bridge
and were subject to the same authority concerning
its use (e.g., the same tower operator
controls trains of both operations), FRA will
exercise jurisdiction in a manner sufficient
to ensure safety at this point of connection.
Also, where transit operations share highway-
rail grade crossings with conventional
railroads, FRA expects both systems to observe
its signal rules. For example, FRA expects
both railroads to observe the provision
of its rule on grade crossing signals that requires
prompt reports of warning system
malfunctions. See 49 CFR part 234. FRA believes
these connections present sufficient
intermingling of the rapid transit and general
system operations to pose significant
hazards to one or both operations and, in the
case of highway-rail grade crossings, to the
motoring public. The safety of highway users
of highway-rail grade crossings can best be
protected if they get the same signals concerning
the presence of any rail vehicles at
the crossing and if they can react the same
way to all rail vehicles.
RAPID TRANSIT CONNECTIONS NOT SUFFICIENT
TO TRIGGER FRA’S EXERCISE OF JURISDICTION
Although FRA could exercise jurisdiction
over a rapid transit operation based on any
connection it has to the general railroad system,
FRA believes there are certain connections
that are too minimal to warrant the
exercise of its jurisdiction. For example, a
rapid transit system that has a switch for receiving
shipments from the general system
railroad is not one over which FRA would assert
jurisdiction. This assumes that the
switch is used only for that purpose. In that
case, any entry onto the rapid transit line by
the freight railroad would be for a very short
distance and solely for the purpose of dropping
off or picking up cars. In this situation,
the rapid transit line is in the same situation
as any shipper or consignee; without
this sort of connection, it cannot receive or
offer goods by rail.
Mere use of a common right-of-way or corridor
in which the conventional railroad and
rapid transit operation do not share any
means of train control, have a rail crossing
at grade, or operate over the same highwayrail
grade crossings would not trigger FRA’s
exercise of jurisdiction. In this context, the
presence of intrusion detection devices to
alert one or both carriers to incursions by
the other one would not be considered a
means of common train control. These common
rights of way are often designed so that
the two systems function completely independently
of each other. FRA and FTA will
coordinate with rapid transit agencies and
railroads wherever there are concerns about
sufficient intrusion detection and related
safety measures designed to avoid a collision
between rapid transit trains and conventional
equipment.
Where these very minimal connections
exist, FRA will not exercise jurisdiction unless
and until an emergency situation arises
involving such a connection, which is a very
unlikely event. However, if such a system is
properly considered a rail fixed guideway
system, FTA’s rules (49 CFR part 659) will
apply to it.