Big John contributed a copy of a hand written booklet "Inventory of Locomotive Engines on the LIRR - 1848".
Post Boy - (my note: along with the Ariel, the Post Boy was one of the first two engines used on the LIRR) - "One of the oldest engines. Requires light repairs - (say $150) and will be capable of running the Farmingdale train. 8 tons. Can take out of the Depot at Brooklyn 3 cars and run to Farmingdale in two hours and make the necessary stops."
John A. King - "Put on the Road in the year 1838. Is now in the shop repainting and will cost about $400 and will then be in good running condition. First Cost (no number shown). 9 Tons. Can take out of the Depot at Brooklyn 3 Long Cars. Can run to Greenport with them in 4 hours."
Brooks - "Put on the Road in the Spring of 1844. Is now nearly good as new, with the exception of the boiler, which will cost about $100 to make good. First cost $6,500. 16 tons. Can take out of the Depot at Brooklyn 7 cars. Can run from Brooklyn to Greenport with 3 cars in 3-1/4 hours."
Fisk - "Put on the Road in the summer of 1844. Is now as good as new. Cost price $6,500. 16 Tons. Can take out of the Depot at Brooklyn 5 Long Cars. Can run from Brooklyn to Greenport with 3 cars in 3-1/4 hours."
...much more to come from this interesting piece of LIRRHistory!
The next picture is the LIRR's first "Double Decker" (it was not a Bi-level as the new diesel/dual mode fleet of C-3's are - there was only one floor and you either walked up or down to the seats, as were all the other double deckers through the 1960's), and the first all-aluminum passenger car ever, # 200. It was built in 1932 and is currently owed by the Railroad Museum of LI, awaiting restoration, as shown in the second picture. The third picture is of the interior of one of the old double deckers.
The LIRR's first Diesel Locomotive (actually the first Diesel locomotive ever!) was #401, pictured here in 1926 on an experimental run. (from the LIRR 125th Anniversary booklet)
S. Berliner has a page devoted to #401 located HERE.
The first electric cars owned by the LIRR were the MP-41's (41 denotes the length of the interior of the car). There were a total of 130-something (I forget the exact number as I write this) of them and they were mostly used on the "Local Electric Service" that lasted until the early 1940's. The last remaining cars of this fleet served on the Mitchel Field shuttle in the early 1950's. Here's a picture of #1026 in 1941 (Ron Ziel collection)
Steve Hoskins contributed the following, to which I am greatly appreciative:
This is what was on hand as of December, 1957
L O C O M O T I V E S
CLASS NUMBERS TYPE BUILT
GS-4 400 GE 44-ton 1950
AS-6 404-408 Alco S-1 1946
AS-6 413-414 Alco S-1 1949
AS-6 417-421 Alco S-1 1949
AS-6C 415-416 Alco S-1 1949
BS-6 403 Baldwin VO660 1945
BS-6a 409-412 Baldwin VO660 1948
AS-10 446-447 Alco S-2 1949
AS-10C 448-449 Alco S-2 1949
AS-10C 451-460 Alco S-2 1949
BS-10aC 450 Baldwin VO1000 1948
AGP-10-SC 461-465 Alco RS-1 1948
AGP-10-MSC 466-469 Alco RS-1 1950
AGP-16-MSC 1551-1560 Alco RS-3 1955
FGP-16-SC 1503 F-M H16-44 1950 ex-Demonstrator
FGP-16-MSC 1501-1502 F-M H16-44 1951
FGP-16-MSC 1504-1505 F-M H16-44 1951
FP-20-SC 2001-2008 F-M CPA20-5 1950

These
are two pictures of the same engine, the first in the original
color scheme and the second in the revised color scheme
FP-24-SC 2401-2404 F-M CPA24-5 1951
Here's
a brochure (contributed by an anonymous reader of this website)
showing a little of the history of these Fairbanks Morse C-Liners
A - Alco
B - Baldwin
F - Fairbanks-Morse
G - General Electric
S - Switcher
GP - General Purpose
P - Passenger
# - horsepower (100)
a - variation in class
C - Automatic Speed Control equipped
S - Steam Generator equipped
M - Multiple unit capability
--------------------------------------------------------------------------
ACQUIRED IN EARLY 1960'S:
AS-10a 439-444 Alco S-2 ex-Delaware & Hudson
AGP-15-MSC 1519-1520 Alco RS-2 ex-Delaware & Hudson
--------------------------------------------------------------------------
P A S S E N G E R C A R
S ( S t e a m )
CLASS CAR NUMBERS BUILT NOTES
Coaches
P-54 139-178 1911-1912
P-54A/P-54B 314-391 1913-1918
P-54D 1-50, 91-138, 462-481 1926-1927
P-54E 452-461 1923
P-70A 390 1911
P-70B 809-810, 812-814 1912-1917
P-72 2901-2980 1955-1956
Club Cars
P-70 811, 826, 828 1912-1916
Combine cars
PB-54 622-627 1911
PB-54C 628-631 1927
PB-57 609-618 1927
Baggage Mail cars
BM-60 717 1928
BM-60B 737-738 1928
BM-62 740-743 1911
BM-62A 747-749 1923
Baggage Express cars
B-60B 715-716, 718-724 1928
B-62 684-689, 739 1910-1911
B-54 619-621 1911
Business car
"Jamaica"
Rail Diesel Cars
RDC-1 3101 1955
Here's some additional pictures of the RDC cars taken by "Merritt" in 1956.
P A S S E N G E R C A R
S ( E l e c t r i c )
Coaches
MP-54A,Ac,AT 1402-1420, 1452-1676 1908-1914

MP54B,Bc,BT 1678-1777 ?
MP-54C,Cc,CT 1784-1943 1920-1927
MP-54D1c 1944-1983 1927
MP-54T 1001-1016, 1421-1450 1908-1923
MP-70 1347 1937 double deck
MP-70A,Ac 1337-1346 1947 double deck
MP-70B,Bc 1287-1336 1948-1949 double deck

MP-70TS 3500-3519 1953
MP-72c 2501-2522 1955
MP-72T 2601-2674 1956
Club cars
CT-54Ac 1677 1913
Combine cars
MPB-54c 1385-1399 1914
MPB-54T 1351, 1363, 1369-1381 1913
Baggage Mail cars
MBM-62c 1209-1210 1910
Baggage Express cars
MB-62c 1205-1208, 1215-1216 1910
MP-62Ac 1211-1214 1910
MB-54T 1348-1349 1910
Passenger Baggage Mail cars
MPBM-54c 1382-1384 1914
Unmotorized trailer coaches
T-54 392-451 1915
T-54A 481-511 1920
T-54B 837-996 1927
T-62 200 1932 double deck
CT-70 201 1937 double deck
T-72 2801-2844 1955
NOTES FOR ALL PASSENGER
CARS:
M - Motorized
C - Club or Control
P - Passenger
B - Baggage
2nd M - Mail
T - Trailer (prefix = unmotorized/suffix - motorized)
## - inside length of passenger compartment
A,B,C,D,E - class variants
c - Automatic Speed Control equipped (cab car)
TS - Trailer, single deck (to differentiate among "70"
classes)
CARS ACQUIRED IN 1960'S:
P-71 8506-8513 ex-DL&W
P-63 8514-8516 ex-Reading
P-69 8517-8522 ex-Delaware & Hudson
P-71A 8523-8528 ex-Pennsylvania
P-74A 7501-7505 ex-New York Central
P-74B 7521-7550 ex-Boston & Maine
P-74B1 8551-8553 ex-Bangor & Aroostook
P-74 parlor cars 2011-2047
I do not have details on, Most are ex-PRR but
some are ex-DL&W; one (2037-Tuscarora Club) is ex-Lehigh Valley
diner.
MP-75c 2525-2536 1963 "World's Fair" cabs

MP-75T 2675-2692 1963 "World's Fair" trailers
The following is from the April, 1963 issue of Railroad Magazine and lists the entire LIRR rolling stock at that time.
Here are some old steam engines scans:
Brooks #145 taken at LIC in 1931
Baldwin #114 taken at Morris Park in 1916
Rogers #47 at Winfield in 1915