Notes on Detailing B&M Diesel Locomotives

Detailing information on some classes of B&M diesel locomotives, much of which was provided by Scott Whitney . My Unofficial B&M Page contains general information on the railroad and a diesel locomotive roster listing engines by groups ordered. In general, as-built data is presented in a table, with notes regarding in-service changes and re-buildings.

Table of Contents

Boston and Maine Cab Signal Equipment

Per the Interstate Commerce Commission's mandate, the Fitchburg Division had been equipped with Cab Signals in the 1930s. The installation was reduced to Ayer - Boston as passenger service to New York and Western Massachusetts ended. Not all B&M motive power had Cab Signals, so equipped units almost always led in the active territory. From the late 1920s to the late 1960s, this was West Cambridge to East Deerfield. By 1976, cab signals had been cut back to West Cambridge - Ayer.

Boston and Maine Switchers With Multiple Unit Controls

Number Model Builder Brakes Specifics
1127 SW-1EMD 6 BLC Both ends installed by Concord Shops
1210NW-2EMD6 BL Both ends factory w/drop steps
1211NW-2EMD6 BL Both ends factory w/drop steps
1212NW-2EMD6 BL Both ends factory w/drop steps
1213NW-2EMD6 BL Both ends factory w/drop steps
1230SW-9EMD6 BL Cab end factory w/drop step
1231SW-9EMD6 BL Cab end factory w/drop step
1272S-4ALCO14 EL Cab end factory w/drop step, 19 Pin
1273S-4ALCO14 EL Cab end factory w/drop step, 19 Pin

Units with 14 EL and ALCO 19 pin M.U. are not able to multiple with any other units.

Units with 6 BL are not able to multiple with units 6 BLC, 24 RL, or 26L except as a trailing unit with independent brake bail-off not available or as a leading unit with some special hookup arrangements by shop personnel.

SW-9 1230 had angled numberboards on the end of the hood like the SW-8s.

Boston and Maine GP-7 Locomotive Details

Number M.U. Winterization Hatch Train Lighting Steam Gen. Air Brakes Notes
155527NOBy 1955YES 24 RL
155627NO By 1955YES 24 RL
155727NO NeverYES 24 RL
155827NO By 1955YES 24 RL
155927NO NeverYES 24 RL
156027NO NeverYES 24 RL
156127NO As deliveredYES 24 RL
156227NO As delivered YES 24 RL
1563NONENO By 1954 YES 6 BL1, 2, 3
1564NONENO By 1954 YES 6 BL2, 3
1565NONENO By 1954 YES 6 BL2, 3
1566NONENO By 1954 YES 6 BL2, 3
1567NONENO By 1954 YES 6 BL2, 3
1568NONENO By 1954 YES 6 BL2, 3
1569NONENO by 1954 YES 6 BL2, 3
1570NONENO By 1954 YES 6 BL2, 3
1571NONENO By 1954 YES 6 BL2, 3
157227 YES As delivered YES 24 RL4
157327 YES As delivered YES 24 RL4
157427 YES As delivered YES 24 RL4
157527 YES As delivered YES 24 RL4
157627 YES As delivered YES 24 RL4
157727 YES As delivered YES 24 RL4


  1. Unit was equipped with a snowplow pilot while still sporting maroon paint during footboard era.
  2. M.U. system as well as drop steps added to these units in late 50's. 1568 did not have MU in early 1957.
  3. Units 1563-1571 underwent gradual changeover to 24 RL brakes, however, some units may not have been completed leading to the eventual restriction of single or trailing unit use.
  4. These units equipped with cab signal equipment for use on Fitchburg Route.

General Notes:

GP-7 locomotives were equipped with old style cab heaters which, during the winter months required that blanking panels be installed over the intake for the number 1 radiator and a round conical doughnut placed over the number 1 fan.

All B&M GP-7 were delivered in maroon with gold striping and Minuteman heralds on the cab sides. Underframes were black with black trucks but most received silver trucks starting in 1953. Eventually all B&M GP-7s were painted 'blue dip'.

1555 - 1571 were delivered with a 3-chime horn, all bells facing forward, mounted on the engineer's side of the short hood. 1572 - 1577 were delivered with a 3-chime horn, center bell facing backwards, mounted on the roof of the short hood. Some engines in this last group also had the openings in the side of the frame skirt above the fuel tank. The last group also had a slightly different footboard arrangement, with a ledge above the footboard about where the MU hose ends would be. None of the engines with MU had the MU hoses on either side of the coupler installed when in general service during the 1950s.

In the early 1960s, the side MU hoses start to appear in photos, and by the late 1960s there are cut-outs in the sloping sheets above the footboards to keep them organized. A few of the earlier engines had one or two of these openings cut out in the 1960s. Several units also had the outboard water tanks removed when shopped, and a few got bells mounted on a bracket on the fireman's side of the front of the short hood.

Boston and Maine RS-2 Details

Number M.U. Headlight Steam Gen. Train Light Brakes Notes
150121/12SINGLE NO NO 6 DS 2
150221/12SINGLE NO NO 6 DS 2
150321/12SINGLE NO NO 6 DS 2
150421/12SINGLE NO NO 6 DS 2
153021/12SINGLE YES NO 6 DS 3
153121/12SINGLE YES NO 6 DS
153221/12SINGLE YES NO 6 DS
153321/12SINGLE YES NO 6 DS
153421/12SINGLE YES NO 6 DS


  1. 1500 was the only RS unit delivered in black switcher style paint; also the only RS-2 ever repainted solid blue.
  2. Steam generators and underbelly water tanks added by November 1953.
  3. Unit received water cooled turbo with crosswise stack, upgraded to 1600 hp.

General Notes:

1501-1504 and 1530-1534 had old style Alco 21/12 pin M.U. system which featured dual M.U. sockets and would only multiple with themselves or 1505 - 1519, provided all moves were done from the dual-system RS-3. M.U. air connections were located above the running boards and there were no drop steps applied to these units.

All RS-2s (except 1500) were delivered in maroon paint with gold striping. The hood tops (above 1" thin gold stripe), the cab roof, the side sill and the side of the square box between the air tanks and the front of the cab side were also maroon. The pilots, steps and the rest of the underbody and trucks were black. The Alco builder's photo shows a Minuteman herald on the end of the long hood with gold outline and letters on a blue or bluish gray background, with no "railroad" underneath.

All RS-2s, including 1500 had their trucks re-painted silver about 1954. Later (as seen in 1960 photos) 1530 and 1532 had black roofs above the pinstripe including the cab front and back as well as black side sills. In 1960 unit 1533 had black side sills. Various styles of heralds were used on the long hood end, some without the white backgrounds, some without the word "railroad" below the Minuteman.

All units had cab signalling equipment located in a box on the running board behind the cab on fireman's side (B&M RS-2s were set up with the long hood forward). Air brake equipment was also located in this area. All RS-2s were delivered with Leslie Super-Tyfon single-chime horns on the hood ahead of and behind the cab.

By 1960, a number of the surviving RS-2s had been rebuilt with water-cooled turbochargers amd crosswise exhaust stacks.

Article on modeling B&M RS-2s and RS-3s in Oct. 2002 Railroad Model Craftsman

Boston and Maine RS-3 Details

Number M.U. Headlight Turbo Train Lighting Air Brakes Notes
153521 TWIN AIR NO 6 SL2,3,5
153621 TWIN AIR NO 6 SL2,3,4,5
153721 TWIN AIR NO 6 SL3,5
153821 TWIN AIR NO 6 SL3,5
153921 TWIN AIR NO 6 SL3,5
154021 TWIN AIR NO 6 SL2,3,5
154121 TWIN AIR NO 6 SL5
154221 TWIN AIR NO 6 SL1,3,5
154321 TWIN AIR NO 6 SL3
154421 TWIN AIR NO 6 SL5
154521 TWIN AIR NO 6 SL3,5


  1. These units were eventually repainted blue.
  2. Units upgraded to 24 RL brakes and AAR 27 pin M.U. systems.
  3. Train lighting equipment with box added to engineer's side of unit near radiator section after delivery.
  4. Unit ran for a period of time with both the top 1" stripe and bottom 4" stripe at base of hood missing.
  5. Unit upgraded to water cooled turbocharger.

General Notes:

All B&M RS-3s were delivered in maroon paint with gold striping. Units 1505-1519 had the Minuteman herald on the cab sides while 1535-1545 had a single herald on the end of long hood. All hood tops, cab tops, and underframes including side sills were painted black. 1505-1519 were delivered with trucks painted silver, others received silver trucks circa 1953-4. All RS-3s were delivered with steam generators.

Units 1505-1519 (as well as at least three others upgraded by the B&M) had both Alco 21 pin and AAR 27 pin M.U. systems. The M.U. air lines had connections both above and below the running boards to facilitate connecting to both EMD and Alco units.

Units 1535-1545 were delivered with Alco 21 pin M.U. and were able to MU among themselves, with MU-equipped RS-2s or (if used in trailing position) 1505-1519. They could not connect to EMD road power unless a dual system unit i.e. 1505-1519 was placed between it and other power. As of 1965, 1535, 1536 and 1540 had received dual Alco/AAR MU. All of the other 1952 RS-3s except 1542 were retired in 1966.

Units 1505-1519 had an extra box ahead of cab on fireman's side resembling a battery box. This was the result of the locomotives having sealed carbodies with filters and this was an air passage.

Units 1535-1545 were Phase I units but had extra large number boards not to be found on many other locos except B&M ALCO S-3 and S-4 switchers.

Units 1505-1519 were Phase III units with large angled number boards attached to the corners of the long and short hoods.

The 1954 RS-3s came with the train-lighting box at the rear side of the radiator on the engineer's side. Some of the 1952 order had similar train-lighting boxes applied after they'd been in service for a while. After the end of locomotive-hauled commuter service, some units from each series had these boxes removed. Units where the box hadn't yet been applied had a standard radiator shutter outline. Units where the box had been removed had a notch in the radiator shutters where the box had been, with louvers.

1535-1545 and 1505-1509 were delivered with 3-trumpet Nathan M-3RT1 (#1 trumpet rear-facing and tilted up) air horns mounted to the front of the cab on a bracket. 1510-1519 were delivered with a 3-chime horn mounted on a sheet metal bracket atop the long hood ahead of the cab.

All units were steam generator equipped.

Cab signal equipment was located on engineer's side of the long hood just ahead of the cab on all units.

As with the GP-7s, photos taken while 1505-1519 were primarily in passenger service do not show the MU air hoses installed on the pilots. Unlike the GP-7s, the pilot openings to protect the hose ends were present at delivery.

Two RS-3's not shown on list, 1546-1547 were received in 1975, traded by the Delaware & Hudson Railroad for B&M RS-3s with working steam generators. They were equipped with Alco 21 pin M.U. and for that reason were always run singly or as a pair. The only exception was one reported use in a lashup with B&M unit 1519 as a splice unit as it was the last remaining true B&M RS-3 running and still had the dual system.

EMD BL-2 detailing

The B&M's BL-2s were delivered in 1949, numbered 1550 - 1553. All had steam generators with the vent in the center post of the windshield (Custom Finishing offers a brass casting in HO), and none had multiple-unit control. As delivered, the end handrails had four stanchions, with a walkway in the center and a drop step. Unlike the LifeLike HO model, all the stanchions were the same length, so the top rail was straight across. Starting in 1950, the drop step was removed, and a continuous, straight handrail supported by only three stanchions was installed. All the BL-2s had received this modification by 1952. At the same time, a reflectorized road number panel was added to both end doors, above the original Minuteman herald.

The only grab irons on the hoods or cab were a single ladder of grabs to the left of the end door in the long hood. A large Leslie A200 single-trumpet air horn faced forward on the short hood. A smaller Leslie A125 faced the rear on the hood behind the fireman.

Article on modeling B&M BL-2s in October 2004 Railroad Model Craftsman

EMD Cab Unit Detailing Overview

Most of the B&M's cab units were received lacking "eyebrow" grab irons above the cab windows and ladder rests on the nose. These were applied to the whole fleet starting about 1950. The F-3As, F-7As and the single E-8 were probably delivered with them - they appear in 1949, 1950 and 1951 photos. 1949 - 1951 photos show that some of the E-7s and F-2s received the ladder rests before they got the "eyebrow" grabs.

All of the B&M's cab units were delivered with freight pilots except for F-7 4268. All of the FTs, F-2s, F-3s and F-7s were delivered with dynamic brakes. None of the E units had them. The FTs and the E-7s were delivered with the small rectangular opening for the coupler with the air plumbed through the pilot in its own hole. F-2, F-3 F-7 and E-8 A-units had the standard D-shaped opening with air and signal sharing the opening with the coupler. Some older units received newer pilots as wreck repairs. None of the A units were ever equipped with MU connectors on the nose. By the mid-1960s, the surviving freight and dual-service A-units were starting to receive "footboards" running forward from the cab ladder, usually on the engineer's side but sometimes on both.

All B&M cab units were delivered with Leslie Tyfon A-200 air horns on the cab roof.

Article on modeling B&M F-2s and E-8s in April 2002 Railroad Model Craftsman

EMD F-7A and F-7B detailing

The B&M's eight F-7s were purchased in two orders: the A-units in 1949 and the B-units in 1950. All were "Phase 1" units, with the roof overhangs at the ends and 36" dynamic brake fans as delivered. None of the A-units had steam generators, but by the early 1960s a few had vents in the rear hatch indicating they were equipped to supply boiler water to a trailing steam-generator equipped B-unit. 4268A was delivered with a passenger-style pilot. The F-7As retained their original fore-and-aft single-chime horn setup through the 1960s. By 1972, 4266A had a 3-chime horn replacing the forward-facing single chime on the engineer's side, but retained the rear-facing single chime opposite.

Although some rosters have listed the B-units as delivered with steam generators, recent research has shown that only a couple of the B-units received boilers from F-2Bs scrapped in the early 1960s. These were 4265B and 4268B, which were used as back-up power for the F-3 A-B sets on the remaining Conn. River passenger trains. The first two B-units (4265B, 4266B) had pointed ends on the roof, the second two had a roofline that was straight across.

EMD FT detailing

The FTs were delivered with the wing herald on the side, only the road number on the nose door, 7-bulb headlights and no 'eyebrow' grabs or ladder rests on the sides of the nose. In the post-war years, they were re-painted with the road name on the side and a Minuteman herald on the nose. The latest photo I've seen showing the wing herald is 4218 A/B in 6/1950. There are a few photos around which have the rectangular "Boston & Maine" on the side, but no Minuteman on the nose. In the mid-1950s, a number received 3-chime horns mounted over the fireman's side of the cab. Photos show this on 4200 (1954, 1956, 1957), 4204 (1954), 4205 (1954) and 4219 (1954). Most of the FTs received a long, narrow rectangular roof-mounted cooling pipe of some sort at the rear of the fireman's side in the 1950s.

EMD E-7 detailing

On the Es, both horn trumpets faced forward. All had 3-chime horns replacing the A200s by 1956.

Budd RDC Detailing

The B&M's RDCs formed three major groups: the Phase 1B cars ordered in 1952 and 1953, the Phase 1C cars ordered in 1955 and early 1956, and the Phase 2 cars ordered between late 1956 and 1958. Details varied from group to group. A roster and more modeling information can be found in my B&M Passenger Equipment page.

Early (Phase 1B) RDCs

The B&M's pre-1955 RDCs were all standard Phase 1B cars with fabricated trucks, except that 6300 had a gap in the curved molding under the baggage door, like a couple of other very early RDC-3s owned by the NYC. They were all delivered with centered single-chime horns, the road name on the letterboard, and unpainted, undecorated stainless steel ends. By 1955 (possibly as early as 1953, if the caption on pg. 35 of the Summer 1981 Bulletin is correct), these cars were receiving Minuteman heralds on the ends. In 1955, the single-chime horns started to be replaced with 2-chime horns offset somewhat towards the engineer's side, but some cars retained the single-chime horns for some time after the Minuteman herald was applied. I believe that all the single-chime horns were gone by the time the cars received the McGinnis white-ended scheme (late 1956, early 1957).

1955 RDC Order (Phase 1C)

The 1955 order of RDCs had a Phase 1C body, but were equipped with the same cast trucks that became standard on Phase 2 RDCs. All were delivered with Minuteman heralds on unpainted stainless steel ends; some had their number applied in reflective material above the herald on the fireman's side. All were delivered with 2-chime air horns offset somewhat towards the engineer's side.

New Look (Phase 2) RDCs

The B&M's Phase 2 RDCs had the same 2-chime horn, but installed on the car centerline a short distance behind the headlight. None had the optional corrugations on the lower portions of the end and vestibule doors, but other details varied:

It appears that none of the B&M's Phase 2 cars had the standard Budd Phase 2 configuration with numberboards in the ends only: Those purchased in 1956 and 1957 replaced the end numberboards with specially-ordered side numberboards located where they had been in Phase 1 cars. The 1958 cars had the end numberboards in addition to the special side numberboards.

RDC Air Horns

Early (pre-1955) RDCs were delivered with a single-trumpet Wabco A-2 horn on each cab roof. Later orders arrived (per Scott) with a 2-chime Nathan P-series horn. By 1956, these had been installed on the older cars. A conical wind/snow screen was mounted over each bell.

Scott Whitney reports that the 6154 had a Nathan P5 air horn with three of the bells removed (blanking plates). However, circa 1970 I spent a good deal of time looking at RDCs and I don't remember the bracket having enough extra room for three more bells. What I've used on my post-1956 models in HO is the Custom Finishing Leslie 2-chime (part #220). Clearly I need to go to Bedford, MA and see what 6211 has, or figure out which issue of Trains had the overhead shot of RDCs under the highway overpass in North Station.

RDC Interiors

Most of the B&M's RDCs had 2/2 walkover seats. Typically, the longer compartment of the car was non-smoking, and upholstered in cloth with a blue/gray pattern. The smoking area was upholstered in red vinyl. The side walls and ceiling were a cream color, yellowed by tobacco smoke to a greater or lesser degree. The end walls and the exhaust duct housing in the middle of the car were a fairly dark pastel red. There were advertising card holders on the end walls and both sides of the duct housing. The floor was tiled in a black/white swirl pattern. The interior of the baggage and mail compartments were pale green. Phase 1 cars had longitudinal flourescent tube fixtures along the center line of the car and incandescent reading lights built into the brackets supporting the luggage racks. Phase 2 cars had much simpler luggage racks, and only the longitudinal flourescent lights. All the B&M RDCs were built with un-tinted glass windows, and kept them until they were replaced with un-tinted plastic in the 1970s.

Cab interiors were bare unpainted stainless steel. The engineer's side had a removeable folding seat - it was moved from cab to cab when changing ends. It could also be folded up under the control stand. The throttle/reverser control housing was grayish-green fiberglass. On cars equipped with Fitchburg Division cab signals, the indicator was mounted to the left of the engineer's end window. The vestibule doors were one piece with a drop sash (as opposed to the dutch doors found on some other railroads' RDCs).

When rock throwing became severe in the late 1960s, the train-door windows were blanked with stainless steel plates and steel gratings were added over the engineer's window. This was about the same time that they stopped applying white paint to the ends; I've never seen white paint on a modified end.

RDCs with Cab Signals:

RDC-1 Phase 1I:
6100, 6101, 6104, 6105, 6146 - 6148
RDC-1 Phase II:
6153 - 6156
RDC-2 Phase 1I:
6212 - 6214

Boston and Maine GP-9 Locomotive Details

All of the GP-9s were delivered with a forward-facing two-chime horn on top of the short (forward) hood, and a larger, rear-facing single chime horn mounted between the forward exhaust stack and the forward radiators. Cab interiors were light green. MU hoses on either side of the coupler are present in all pictures.

One set of three units received silver trucks for the first trip of a new TOFC service circa 1960. I haven't seen any evidence that this lasted more than a few weeks.

The use of dynamic brakes was banned on the B&M after about 1969. Those on the GP-9s were not maintained after this point. In the late 1970s, Billerica rebuilt a number of units; they received new numbers in the 1800 series and the Blue Dip scheme if they hadn't previously. Most, if not all had their dynamic brake blisters blanked.

Athearn's B&M GP-9 in the Bluebird scheme has correct paint and correct horn layout. They were done after the revisions to the location of the radiator intakes prompted by complaints about the initial batch of engines (not B&M), but some may not be satisfied with the size of the cab windows.

Boston and Maine 44-Ton Locomotive Details

Most units were delivered with a single WABCO horn. Late units came with a 2-chime WABCO. Most were refitted with Nathan P-2 horns. Some eventually received 3-chime horns, either P-3 or M-3.

Early 44-tonners arrived in black with rectangular heralds. After WWII all received red/silver nose stripes and Minuteman heralds. Trucks were painted silver starting in 1953. Most of those that survived past 1968 received 'blue dip'.

#110-113 (1940) were delivered with a single set of steps over one truck on each side. This was modified to steps at all four corners between 1951 and 1953.

#110 and #114 received diagonal safety stripes on their pilots around 1953.

#118-9 had headlight visors with number boards. Other 44-tonners had small number boards built into the hoods.

Personal notes (Scott Whitney):

Maintained by James VanBokkelen.