1398 LAWS OF MARYLAND. [Cn. 561

another project or projects shall not be effectual until the
principal of and the interest on the bonds issued in connection
with the first mentioned project shall have been paid or pro-
vision made for their payment, or the Commission may there-
after charge tolls for the use of any such project in order to
provide funds for reimbursing the Commission any sum there-
tofore expended in paying a part of the cost of maintaining,
repairing and operating such project, and such tolls may be
continued until such sum shall have been reimbursed to the
Commission.

122Q. (Preliminary Expenses.) The Commission is here-
by authorized to expend out of any funds available for the
purpose such moneys as may be necessary for the study of
any project or projects and to use its engineering and other
forces, and the services of consulting engineers and traffic
engineers, for the purpose of effecting such study and to pay
for such additional engineering and traffic and other expert
studies as it may deem expedient, and all such expenses in-
curred by the Commission prior to the issuance of revenue
bonds under the provisions of this sub-title shall be paid by
the Commission and charged to the appropriate project or
projects, and the Commission shall keep proper records and
accounts showing each amount so charged. Upon the sale
of revenue bonds for any project or projects, the funds so
expended by the Commission in connection with such project
or projects shall be reimbursed to the Commission from the
proceeds of such bonds.

122R. (Revenue Refunding Bonds.) The Commission is
hereby authorized to provide by resolution for the issuance
of revenue refunding bonds of the State for the purpose of
refunding any bonds then outstanding which shall have been
issued under the provisions of this sub-title, including the
payment of any redemption premium thereon and any inter-
est accrued or to accrue to the date of redemption of such
bonds, and, if deemed advisable by the Commission, for the
additional purpose of constructing improvements, extensions
or enlargements of the project or projects in connection
with which the bonds to be refunded shall have been issued.
The Commission is further authorized to provide by resolu-
tion for the issuance of revenue bonds of the State for the
combined purpose of (a) refunding any revenue bonds or
revenue refunding bonds then outstanding which shall have
been issued under the provisions of this sub-title or under
the provisions of Sections 123 to 140, inclusive, of this Article
(sub-title "Revenue Bonds"), including the payment of any
redemption premium thereon and any interest accrued or