1992 CENSUS OF TRANSPORTATION, COMMUNICATIONS, AND
UTILITIES

=>GENERAL

The 1992 Census of Transportation, Communications, and Utilities, part
of the 1992 Economic Census, covered transportation, communications,
and utilities as defined in Division E of the 1987 Standard Industrial
Classification (SIC) Manual, (Standard Industrial Classification Manual: 
1987.  For sale by Superintendent of Documents, U.S. Government
Printing Office, Washington, DC  20402.  Stock No. 041-001-00314-2)
except for SIC Major Group 43, United States Postal Service.

Data are presented for establishments in the following classifications (data
presented for SIC Major Group 40, Railroad transportation, were reported
to the Association of American Railroads and published in Railroad Facts,
1993 edition.  These data are shown for the United States only.)  (Data
presented for SIC Major Group 45, Transportation by air, include revenue
for large certificated passenger carriers that was reported to the office of
Airline Statistics, U.S. Department of Transportation, as published in Air
Carrier Financial Statistics Quarterly.  These data are shown for the
United States only.):

SIC code       Title

40             Railroad transportation
41             Local and suburban transit and interurban highway
               passenger transportation
42             Motor freight transportation and warehousing
44             Water transportation
45             Transportation by air
46             Pipelines, except natural gas
47             Transportation services
48             Communications
49             Electric, gas, and sanitary services

The Miscellaneous Subjects report, which includes Revenue Lines data,
does not include firms without paid employees and governmental
organizations classified in the covered industries.

For firms classified in Pipelines, except natural gas (SIC 46); Telephone,
telegraph, and other message communications (SIC 481 and 482); and
Electric and gas services (SIC 491, 492, and 493), the basic tabulations in
this report include establishments which are auxiliary (primary function is
providing a service, such as an administrative office) to other
establishments within the same organization.  For firms classified in all
other industries covered by this report, the basic tabulations do not include
data for auxiliary establishments.  Data for those auxiliaries are presented
in a subsequent report issued as part of the 1992 Enterprise Statistics
reports.

For the 1992 Census of Transportation, Communications, and Utilities,
large- and medium-size firms, plus all firms known to operate more than
one establishment, were sent questionnaires to be completed and returned
to the Census Bureau by mail.  For selected very small firms, data from
existing administrative records of other Federal agencies were used
instead.  These records provided basic information on location, kind of
business, revenue, payroll, number of employees, and legal form of
organization.  In addition, more detailed information for selected small
employer firms was obtained on the various questionnaires.

=>CENSUS DISCLOSURE RULES

In accordance with Federal law governing census reports, no data are
published that would disclose the operations of an individual establishment
or business.  However, the number of establishments in a kind-of-business
classification is not considered a disclosure, so this information may be
released even though other information is withheld.

=>GEOGRAPHIC AREAS COVERED

The Revenue Lines CD-ROM presents data for the following areas:

1.   The United States as a whole.

2.   States including the District of Columbia and Selected States.

3.   Each consolidated metropolitan statistical area (CMSA) and
     primary metropolitan statistical area (PMSA) defined by the Office
     of Management and Budget (OMB) as of June 30, 1993.  A CMSA
     is an area used to facilitate the presentation and analysis of data for
     large concentrations of metropolitan populations.  It includes two
     or more contiguous PMSA's which have a population of at least
     1,000,000 (according to 1990 Census of Population or subsequent
     special census) and which meet specific criteria of urban character
     and of social and economic integration.

4.   Selected metropolitan statistical areas (MSA) defined by the OMB
     as of June 30, 1993.  An MSA is an integrated economic and
     social unit with a population nucleus of at least 50,000 inhabitants
     (according to 1990 Census of Population or subsequent special
     census).  Each MSA consists of one or more counties meeting
     standards of metropolitan character; in New England, cities and
     towns rather than counties are the component geographic units.

The accuracy of these tabulated data is determined by the joint effects of
the various nonsampling errors.  No direct measurement of these effects
has been obtained except for estimation for missing or misreported data;
however, precautionary steps were taken in all phases of the collection,
processing, and tabulation of the data in an effort to minimize the effects
of nonsampling errors.

The Bureau of the Census obtains on computer tape limited information
extracted from administrative records of other Federal agencies.  This
information is used in conjunction with other information available to the
Census Bureau to develop estimates for nonemployers, small employers,
and other establishments for which responses were not received in time for
publication.

=>DOLLAR VALUES

All dollar values presented in this report are expressed in current dollars,
i.e., 1992 data are expressed in 1992 dollars and 1987 data in 1987
dollars.  Consequently, when making comparisons to prior years, users of
the data should consider the inflation that has occurred.

=>RELIABILITY OF DATA

All data compiled in this report originated from either census
questionnaires or administrative records of other Federal agencies and,
therefore, are not subject to sampling errors.  However, the data are
subject to nonsampling errors.  Nonsampling errors can be attributed to
many sources:  inability to identify all cases in the actual universe;
definition and classification difficulties; differences in the interpretation of
questions; errors in recording or coding the data obtained; and other
errors of collection, response, coverage, and estimation for missing or
misreported data.

The accuracy of these tabulated data is determined by the joint effects of
the various nonsampling errors.  No direct measurement of these effects
has been obtained except for estimation for missing or misreported data;
however, precautionary steps were taken in all phases of the collection,
processing, and tabulation of the data in an effort to minimize the effects
of nonsampling errors.

The Bureau of the Census obtains on computer tape limited information
extracted from administrative records of other Federal agencies.  This
information is used in conjunction with other information available to the
Census Bureau to develop estimates for nonemployers, small employers,
and other establishments for which responses were not received in time for
publication.

=>SPECIAL TABULATIONS

Special tabulations of data collected in the 1992 Census of Transportation,
Communications, and Utilities may be obtained, depending on availability
of time and personnel, on diskette, computer tape, or in tabular form. 
The data will be in summary form and subject to the same rules
prohibiting disclosure of confidential information (including name,
address, kind of business, or other data for individual business
establishments or companies) as are the regular publications.

Special tabulations are prepared on a cost basis.  A request for a cost
estimate, as well as exact specifications on the type and format of the data
to be provided, should be directed to the Chief, Services Division, Bureau
of the Census, Washington, DC 20233.  To discuss a special tabulation
before submitting specifications, call 1-800-541-8345.