Until now!
Sure enough, in Mr Scalzo's files there is are copies of an original TCR company roster dated April 1918. Photos (albeit not great quality photos) of the six pages of this roster are at the bottom of this post, following a condensed summary roster. This is not an all-time roster, in that any cars retired before 1918 or acquired after that date are not included. That's a sizable group: some 90 cars were destroyed in a 1913 car barn fire and don't appear on this roster. Even so it does have an incredible amount of information on the cars TCR owned as of 1918 and a bit of information has been added from other sources to fill in a few of the gaps. Photos are from www.newdavesrailpix.com except where noted.
Single truck (closed)
2, 11, 25, 56, #? (5 cars) - St Louis Car (year?), L=26'7", McGuire truck, 2xGE 57 motors, K-11 control, ? seats, hand brake (a)
Rock Island County Historical Society
Augustana College
23 (10 cars including this number) - Cincinnati 1909 ord#1080, L=33' (b)
35 - St Louis Car (year?), L=26'7", 2xGE 52 motors, K-11 control, ? seats, hand brake
247 - St Louis Car (year?), L=26'7", 2xGE 52 motors, K-10 control, ? seats, hand brake (c)
Electric Railway Review
Photo from SchuetzenPark.info
Double truck (closed)
6, 8, 10 - Stephenson (1902?), L=41'0", McGuire trucks, 4xGE 67 motors, K-6 control, 44 seats, Christianson AA1 pump (d)
Augustana College
Augustana College
12,14 - Cincinnati c1903? ord#145, L=43'5", McGuire trucks, 4 x GE 67 motors, K-6 control, 44 seats, Christianson AA1 pump (e)
53 - builder/year?, L=38'10", Std O-50 trucks, 4xGE 80 motors, K-28B control, 40 seats, Christianson AB1 pump
79, 81 - builder/year?, L=36'0", McGuire trucks, 2xGE 67 motors, K-10 control, 36 seats, Christianson AA1 pump (f)
Electric Railway Review
200-207, 209-210, 212-213, 216-217, 219, 222, 227, 230-232, 237 (21 cars) - Tri-City Railway 1900-1903, L=40'7", Brill 27G trucks, 4xGE 52 motors, K-12 control, 40 seats, Christianson AA1 pump (g)
Krambles-Peterson Archive
211, 214-215, 218, 220-221, 223-226, 234, 236 (12 cars) - Tri-City Railway 1901-1903, L=40'7", Brill 27G trucks, 4xGE 52 motors, K-12 control, 44 seats, Christianson AA1 pump (h)
Period postcard; may show car 241 but not certain
242-243 - St Louis Car 1904 ord#463A, L=41'2", Standard O-50 trucks, 4xGE 80 motors, K-28B control, ? seats, GE CP27 pump (j)
244 - Tri-City Railway 1917, L=42'2", Brill 27G trucks, 4xGE 52 motors, K-12 control, 44 seats, GE CP27 pump
Car 284 after conversion to a salt spreader; photo from Iowa Trolleys
280-285 (6 cars) - Chicago Surface Lines 1917, L=39'8", Curtis trucks, 4xGE 52 motors, K-12 control, 40 seats, Christianson AA1 pump (k)
Rock Island Public Library
Electric Railway Journal
307-326 (20 cars) - Chicago Surface Lines 1918, L=40'8", Peckham CUT trucks, 2xGE 57 motors, K-35 control, 44 seats, Christianson AA1 pump (n)
408-415 (8 cars) - Cincinnati 1910 ord#1310, L=44'8" (p)
414-415 - Cincinnati 1910 ord#1290, L=44'9", Standard O-50 trucks, 4xGE 67 motors, K-28B control, 42 seats, GE CP27 pump (q)
Otto Vondrak Collection
416-425 (10 cars) - St Louis Car 1912 ord#918, L=45'0", Standard O-50 trucks, 4xWH 323 motors, K-35G control, 40 seats, GE CP27 pump (r)
George Krambles photo, Krambles-Peterson Archive
426-450 (25 cars) - St Louis Car 1913 ord#998, L=45'0", Bay State 12 trucks, 4xWH 323 motors, K-35G control, 40 seats, GE CP27 pump
David Sebben Collection
451-485 (35 cars) - American Car 1913, L=43'1", Brill 51E1 trucks, 4 x WH 323 motors, K-35G control, 40 seats, GE CP27 pump (s)
486-495 (10 cars) - St Louis Car 1913 ord#998, Bay State 12 trucks, 4xGE 200 motors, K-35G control, 40 seats, GE CP27 pump (t)
David Sebben Collection
505-507 (3 cars) - St Louis Car 1916 ord#1107, L=30'1", Standard O-50 trucks, 4xGE 80 motors, K-28U control, 44 seats, GE CP27 pump (u)
601-606 (6 cars) - American Car 1923 ord#1329, L=38'6", Brill 77E1 trucks (v)
1450, 1486 - Chicago Surface Lines 1917, L=39'8", Curtis trucks, 4xGE 52 motors, K-12 control, 40 seats, Christianson AA1 pump (w)
Single truck (open)
64-69, 74, 77, 79, 80-84 (14 cars) - Pullman (year?), L=26'11", McGuire truck, 2xGE 57 motors, K-10 control, 45 seats, hand brake (x)
Davenport Public Library
Double truck (open)
3, 5 - American Car (year?), L=35'0", McGuire trucks, 2 x GE 80 motors, K-10 control, National A3 pump (z)
Augustana College
Period postcard view
7, 9, 11, 13 - St Louis Car (year?), L=37'5", McGuire trucks, 2 x GE 67 motors, K-10 control, Christianson AA1 pump (aa)
2-8 (7 cars) - ST snow sweepers - McGuire 1913, L=28'2", McGuire truck, 2xGE 52 motors, K-10 control, hand brake (bb)
299 - DT sprinkler - Brill 1910 ord#17268, L=32'6", Brill 27G2 trucks, 4 x WH 101B2 motors, K-28B control, National pump (cc)
R1 - ST flat motor - Tri-City Railway (year?), L=25'0", McGuire trucks, 2 x GE 54 motors, K-10 control, hand brake
"Moline" - DT flat car - Tri-City Railway (year?), L=28'0", McGuire trucks, no motors
"City of Davenport" -ST - L=18'0", McGuire 211 truck, 2xGE 67 motors, K-11 control, National pump (dd)
"Jumbo" - DT - 4 x GE 80 motors (ee)
Notes
(a) Car 25 had GE 52 motors
(b) This listing not in the 1918 roster but rather sourced from Cincinnati Car Co order list; it's possible that all ten cars of this series were destroyed in the 1913 barn fire*
(c) Car 247's condition as of 1918 listed as "junk"
(d) Car 8 had K-28B control and only 42 seats; these three cars are thought to have been acquired from the Moline, East Moline & Watertown, a suburban line absorbed in 1913. The MEM&W began service in 1902 with four Stephenson cars (including a car numbered 6), two 12-bench open cars built by Jackson & Sharp, and a Wason plow. It is not obvious whether any of the other MEM&W equipment (other than cars 6-14, even only) was still on the TCR roster as of 1918.
(e) Acquired from the Moline, East Moline & Watertown
(f) Cars 79 and 81 may have been single-truck; note too that the TCR roster includes two different cars numbered 79 and two different cars numbered 81, the duplicates to these being single-truck open cars
(g) Rebuilt as PAYE cars - cars 200-203 built 1900, 204-222 built 1901, 227 built 1902, 230-237 built 1903; cars 201, 210, 212, 217 had Standard O-50 trucks; cars 201 and 217 had 4xGE 67 motors; cars 202, 210, 212 had 4xGE 80 motors; car 210 had K-10 control; car 212 had K-28U control; cars 202-206, 227, and 237 had GE CP27 pumps
(h) Cars 211-221 built 1901, 223-226 built 1902, 234-236 built 1903; car 211 had Brill 39E1 trucks; car 211 had 2xGE 67 motors; car 221 had 2xGE 80 motors; car 234 had 4xGE 54 motors; car 211 had K-10 control; car 214 had a WH pump; car 234 had a GE CP27 pump; judging from gaps in the roster it seems likely that cars 208, 228-229, 233, and 235 were lost at some point, most likely in the 1913 barn fire*
(i) According to Alan Lind's book on SLCC, cars 238-243 were bought in 1907 from Davenport & Suburban, were originally fitted with St Louis 47 trucks (possibly what TCR termed "St L O-O" trucks), and car 240 was later sold to the Rock Island Southern as RIS #2; cars 238-243 may have been similar to the Chicago "Matchboxes," at the time a commonly-offered SLCC design
(j) Car 243 had St Louis O-O trucks and 4xGE 70 motors
(k) PAYE cars; ex-"Bowling Alley" unrebuilt 1429-1505 series cars built c1899 by Chicago Union Traction; 284 and 285 (and possibly others) later converted to salt spreaders
(m) PAYE cars; car 306 had Standard O-50 trucks; probably rebuilt from open cars (existing photo of car 306 depicts an open car), possibly by SLCC in 1917 (doesn't show up in SLCC order list)
(n) PAYE cars; ex-Chicago Union Traction open cars rebuilt by CSL for resale, initially equipped for two-car train operation for use in Arsenal service
(p) This listing not in the 1918 roster but rather sourced from Cincinnati Car Co order list; cars 408-415 were all destroyed in the 1913 barn fire*
(q) Originally cars 401-407 (7 cars) were built on this order but five were burned up in the 1913 barn fire*; cars 403 and 407 were renumbered as 414-415.
(r) PAYE cars; cars 423-425 had Brill 51E1 trucks; cars 416-420 had 4xGE 80 motors; car 428 had 4xGE 200 motors; originally 20 cars numbered 416-435 were built on this order but 10 were destroyed in the 1913 barn fire* and the remaining cars were renumbered 416-425
(s) PAYE cars; one car from this series (number unknown) is preserved at IRM as a car body
(t) PAYE cars; built as Cedar Rapids & Marion City 41-50, purchased by TCR in 1914
(u) PAYE cars; car 505 had Brill 51E1 trucks
(v) This listing not in 1918 roster but rather sourced from American Car Co order list
(w) PAYE cars; bought secondhand from CSL in 1917 (Alan Lind's CSL book says 1486 was sold in 1914 while 1450 was sold in 1917), built c1899 by Chicago Union Traction, apparently these cars were not renumbered or hadn't been renumbered yet at the time the 1918 roster was made
(x) Car 77 had a Brill 21E truck; cars 64, 65, 67, 74, and 81 had GE 52 motors; car 65 was a trailer
(y) Originally cars 85-94 (10 cars) were built by SLCC on order #108 but by 1918 only one appears to have still been in service
(z) Car 5 noted as having no motors
(aa) Car 7 had Bemis 40 trucks; cars 7 and 11 had K-6 control; car 7 noted as having no motors; a photo also exists of a double-truck open car numbered 306 but this car may have been renumbered or destroyed in the 1913 barn fire*
(bb) Two of the sweepers were sold in 1936 to Chicago & West Towns #18-19
(cc) Later rebuilt as snow plow
(dd) "City of Davenport" marked as poor condition
(ee) very little information marked for "Jumbo"
*In the June 1, 1913 barn fire, a total of 94 cars were lost. Working from the above roster and builder order lists this total most likely included: 23 series (10 cars), 200-236 series (5 cars), 401-407 series (5 cars), 408-415 series (8 cars), 416-435 series (10 cars), and possibly 85-94 series? (9 cars). That leaves, at minimum, some 47 cars lost in the fire not shown on this roster. Other obvious number series gaps such as 245-246, 248-252, 259-265, and 267 may also have been among the lost cars.
In later years cars were painted yellow with a red stripe at the belt rail. The exceptions were cars used in Bridge Line service between Rock Island and Davenport via Arsenal Island, which had a green livery. Cars delivered around 1913 may have been overall yellow when new. Hand-colored postcards suggest pre-1913 colors were dark green with white or cream along the windows but this is suspect given the source.
