[1] There are two important secondary techniques for opening subterranean and subaqueous ways, neither a method truly of tunneling. One of these, of ancient origin, used mainly in the construction of shallow subways and utility ways, is the “cut and cover” system, whereby an open trench is excavated and then roofed over. The result is, in effect, a tunnel. The concept of the other method was propounded in the early 19th century but only used practically in recent years. This is the “trench” method, a sort of subaqueous equivalent of cut and cover. A trench is dredged in the bed of a body of water, into which prefabricated sections of large diameter tube are lowered, in a continuous line. The joints are then sealed by divers, the trench is backfilled over the tube, the ends are brought up to dryland portals, the water is pumped out, and a subterranean passage results. The Chesapeake Bay Bridge Tunnel (1960-1964) is a recent major work of this character.
[2] In 1952 a successful machine was developed on this plan, with hardened rollers on a revolving cutting head for disintegrating the rock. The idea is basically sound, possessing advantages in certain situations over conventional drilling and blasting systems.
[3] In 1807 the noted Cornish engineer Trevithick commenced a small timbered drift beneath the Thames, 5 feet by 3 feet, as an exploratory passage for a larger vehicular tunnel. Due to the small frontal area, he was able to successfully probe about 1000 feet, but the river then broke in and halted the work. Mine tunnels had also reached beneath the Irish Sea and various rivers in the coal regions of Newcastle, but these were so far below the surface as to be in perfectly solid ground and can hardly be considered subaqueous workings.
[4] Unlike the Brunel tunnel, this was driven from both ends simultaneously, the total overall progress thus being 3 feet per shift rather than 18 inches. A top speed of 9 feet per day could be advanced by each shield under ideal conditions.
[5] Ideally, the pressure of air within the work area of a pneumatically driven tunnel should just balance the hydrostatic head of the water without, which is a function of its total height above the opening. If the air pressure is not high enough, water will, of course, enter, and if very low, there is danger of complete collapse of the unsupported ground areas. If too high, the air pressure will overcome that due to the water and the air will force its way out through the ground, through increasingly larger openings, until it all rushes out suddenly in a “blowout.” The pressurized atmosphere gone, the water then is able to pour in through the same opening, flooding the workings.
Paper 41 - Transcriber’s Note
All obvious typographical errors corrected. Formatting inconsistancies and spelling were standardized. Paragraphs split by illustrations were rejoined.
Transcription of the text in Figure 22. The text was transcribed with a slight modification to the figure description portion.
OPEN TO THE PUBLIC EVERY DAY (Sundays excepted)
from Seven in the Morning, until Eight in the Evening,
THE THAMES TUNNEL.
Fig. 1 shows a transverse section of the Thames, and beneath it a longitudinal section of the Tunnel, as it will be when completed; with the ascents in the inclinations in which they will be finished.
Fig. 2 shows the two arched entrances of the Tunnel from the shaft.
Fig. 3 is a representation of the iron shield, and shows a workman in each of the compartments.
The Entrance to the Tunnel is near to Rotherhithe Church, and nearly opposite to the London-Docks. The nearest landing place from the river is Church Stairs. The Greenwich and Deptford coaches which go the lower road, start hourly from Charing-cross, and Gracechurch-street, and pass close by the works at Rotherhithe.
Books relative to the Tunnel may be had at the works.
The Public may view the Tunnel every day (Sundays excepted) from Seven in the morning until Eight in the Evening, upon payment of One Shilling each Person.
The extreme northern end of the Tunnel is for the present secured by a strong wall; but visitors will find a dry, warm, and gravelled promenade, as far as to almost the centre of the river, and brilliantly lighted with oil gas.
The entrance is from Rotherhithe Street, and by a safe, commodious, and easy stair case.
H. Teape & Son, Printers, Tower-hill, London.
Contributions from
The Museum of History and Technology.
Paper 42
The “Pioneer”: Light Passenger Locomotive of 1851
In the Museum of History and Technology
John H. White
| THE CUMBERLAND VALLEY RAILROAD | 244 |
| SERVICE HISTORY OF THE “PIONEER” | 249 |
| MECHANICAL DESCRIPTION OF THE “PIONEER” | 251 |
| FOOTNOTES | |
| INDEX |
Figure 1.—The “Pioneer,” built in 1851, shown here as renovated and exhibited in the Museum of History and Technology, 1964. In 1960 the locomotive was given to the Smithsonian Institution by the Pennsylvania Railroad through John S. Fair, Jr. (Smithsonian photo 63344B.)
The “PIONEER”:
LIGHT PASSENGER LOCOMOTIVE
of 1851
In the Museum of History and Technology
In the mid-nineteenth century there was a renewed interest in the light, single-axle locomotives which were proving so very successful for passenger traffic. These engines were built in limited number by nearly every well-known maker, and among the few remaining is the 6-wheel “Pioneer,” on display in the Museum of History and Technology, Smithsonian Institution. This locomotive is a true representation of a light passenger locomotive of 1851 and a historic relic of the mid-nineteenth century.
The Author: John H. White is associate curator of transportation in the Smithsonian Institution’s Museum of History and Technology.
The “Pioneer” is an unusual locomotive and on first inspection would seem to be imperfect for service on an American railroad of the 1850’s. This locomotive has only one pair of driving wheels and no truck, an arrangement which marks it as very different from the highly successful standard 8-wheel engine of this period. All six wheels of the Pioneer are rigidly attached to the frame. It is only half the size of an 8-wheel engine of 1851 and about the same size of the 4—2—0 so common in this country some 20 years earlier. Its general arrangement is that of the rigid English locomotive which had, years earlier, proven unsuitable for use on U.S. railroads.
These objections are more apparent than real, for the Pioneer, and other engines of the same design, proved eminently successful when used in the service for which they were built, that of light passenger traffic. The Pioneer’s rigid wheelbase is no problem, for when it is compared to that of an 8-wheel engine it is found to be about four feet less; and its small size is no problem when we realize it was not intended for heavy service. Figure 2, a diagram, is a comparison of the Pioneer and a standard 8-wheel locomotive.
Since the service life of the Pioneer was spent on the Cumberland Valley Railroad, a brief account of that line is necessary to an understanding of the service history of this locomotive.
The Cumberland Valley Railroad
The Cumberland Valley Railroad (C.V.R.R.) was chartered on April 2, 1831, to connect the Susquehanna and Potomac Rivers by a railroad through the Cumberland Valley in south-central Pennsylvania. The Cumberland Valley, with its rich farmland and iron-ore deposits, was a natural north-south route long used as a portage between these two rivers. Construction began in 1836, and because of the level valley some 52 miles of line was completed between Harrisburg and Chambersburg by November 16, 1837. In 1860, by way of the Franklin Railroad, the line extended to Hagerstown, Maryland. It was not until 1871 that the Cumberland Valley Railroad reached its projected southern terminus, the Potomac River, by extending to Powells Bend, Maryland. Winchester, Virginia, was entered in 1890 giving the Cumberland Valley Railroad about 165 miles of line. The railroad which had become associated with the Pennsylvania Railroad in 1859, was merged with that company in 1919.
By 1849 the Cumberland Valley Railroad was in poor condition; the strap-rail track was worn out and new locomotives were needed. Captain Daniel Tyler was hired to supervise rebuilding the line with T-rail, and easy grades and curves. Tyler recommended that a young friend of his, Alba F. Smith, be put in charge of modernizing and acquiring new equipment. Smith recommended to the railroad’s Board of Managers on June 25, 1851, that “much lighter engines than those now in use may be substituted for the passenger transportation and thereby effect a great saving both in point of fuel and road repairs….”[1] Smith may well have gone on to explain that the road was operating 3- and 4-car passenger trains with a locomotive weighing about 20 tons; the total weight was about 75 tons, equalling the uneconomical deadweight of 1200 pounds per passenger. Since speed was not an important consideration (30 mph being a good average), the use of lighter engines would improve the deadweight-to-passenger ratio and would not result in a slower schedule.
The Board of Managers agreed with Smith’s recommendations and instructed him “… to examine the two locomotives lately built by Mr. Wilmarth and now in the [protection?] of Captain Tyler at Norwich and if in his judgment they are adequate to our wants … have them forwarded to the road.” [2] Smith inspected the locomotives not long after this resolution was passed, for they were on the road by the time he made the following report [3] to the Board on September 24, 1851:
In accordance with a resolution passed at the last meeting of your body relative to the small engines built by Mr. Wilmarth I proceeded to Norwich to make trial of their capacity—fitness or suitability to the Passenger transportation of our Road—and after as thorough a trial as circumstances would admit (being on another Road than our own) I became satisfied that with some necessary improvements which would not be expensive (and are now being made at our shop) the engines would do the business of our Road not only in a manner satisfactory in point of speed and certainty but with greater ultimate economy in Expenses than has before been practised in this Country.
Figure 2.—Diagram comparing the Pioneer (shaded drawing) with the Columbia, a standard 8-wheel engine of 1851. (Drawing by J. H. White.)
|
Columbia |
Pioneer |
After making the above trial of the Engines—I stated to your Hon. President the result of the trial—with my opinion of their Capacity to carry our passenger trains at the speed required which was decidedly in favor of the ability of the Engines. He accordingly agreed that the Engines should at once be forwarded to the Road in compliance with the Resolution of your Board. I immediately ordered the Engines shipped at the most favorable rates. They came to our Road safely in the Condition in which they were shipped. One of the Engines has been placed on the Road and I believe performed in such a manner as to convince all who are able to judge of this ability to perform—although the maximum duty of the Engines was not performed on account of some original defects which are now being remedied as I before stated.
Within ten days the Engine will be able to run regularly with a train on the Road where in shall be enabled to judge correctly of their merits.
An accident occurred during the trial of the Small Engine at Norwich which caused a damage of about $300 in which condition the Engine came here and is now being repaired—the cost of which will be presented to your Board hereafter. As to the fault or blame of parties connected with the accident as also the question of responsibility for Repairs are questions for your disposal. I therefore leave the matter until further called upon.
The Expenses necessarily incurred by the trial of the Engines and also the Expenses of transporting the same are not included in the Statement herewith presented, the whole amount of which will not probably exceed $400.00.
These two locomotives became the Cumberland Valley Railroad’s Pioneer (number 13) and Jenny Lind (number 14). While Smith notes that one of the engines was damaged during the inspection trials, Joseph Winters, an employee of the Cumberland Valley who claimed he was accompanying the engine enroute to Chambersburg at the time of their delivery, later recalled that both engines were damaged in transit.[4] According to Winters a train ran into the rear of the Jenny Lind, damaging both it and the Pioneer, the accident occurring near Middletown, Pennsylvania. The Jenny Lind was repaired at Harrisburg but the Pioneer, less seriously damaged, was taken for repairs to the main shops of the Cumberland Valley road at Chambersburg.
Figure 3.—“Pioneer,” about 1901, showing the sandbox and large headlamp. Note the lamp on the cab roof, now used as the headlight. (Smithsonian photo 49272.)
While there seems little question that these locomotives were not built as a direct order for the Cumberland Valley Railroad, an article[5] appearing in the Railroad Advocate in 1855 credits their design to Smith. The article speaks of a 2—2—4 built for the Macon and Western Railroad and says in part:
This engine is designed and built very generally upon the ideas, embodied in some small tank engines designed by A. F. Smith, Esq., for the Cumberland Valley road. Mr. Smith is a strong advocate of light engines, and his novel style and proportions of engines, as built for him a few years since, by Seth Wilmarth, at Boston, are known to some of our readers. Without knowing all the circumstances under which these engines are worked on the Cumberland Valley road, we should not venture to repeat all that we have heard of their performances, it is enough to say that they are said to do more, in proportion to their weight, than any other engines now in use.
The author believes that the Railroad Advocate’s claim of Smith’s design of the Pioneer has been confused with his design of the Utility (figs. 6, 7). Smith designed this compensating-lever engine to haul trains over the C.V.R.R. bridge at Harrisburg. It was built by Wilmarth in 1854.
Figure 5.—An early broadside of the Cumberland Valley Railroad.
According to statements of Smith and the Board of Managers quoted on page 244, the Pioneer and the Jenny Lind were not new when purchased from their maker, Seth Wilmarth. Although of recent manufacture, previous to June 1851, they were apparently doing service on a road in Norwich, Connecticut. It should be mentioned that both Smith and Tyler were formerly associated with the Norwich and Worcester Railroad and they probably learned of these two engines through this former association. It is possible that the engines were purchased from Wilmarth by the Cumberland Valley road, which had bought several other locomotives from Wilmarth in previous years. It was the practice of at least one other New England engine builder, the Taunton Locomotive Works, to manufacture engines on the speculation that a buyer would be found; if no immediate buyers appeared the engine was leased to a local road until a sale was made.[6]
Regarding the Jenny Lind and Pioneer, Smith reported[7] to the Board of Managers at their meeting of March 17, 1852:
The small tank engines which were purchased last year … and which I spoke in a former report as undergoing at that time some necessary improvements have since that time been fairly tested as to their capacity to run our passenger trains and proved to be equal to the duty.
The improvements proposed to be made have been completed only on one engine [Jenny Lind] which is now running regularly with passenger trains—the cost of repairs and improvements on this engine (this being the one accidentally broken on the trial) amounted to $476.51. The other engine is now in the shop, not yet ready for service but will be at an early day.
Figure 6.—The “Utility” as rebuilt to an 8-wheel engine, about 1863 or 1864. It was purchased by the Carlisle Manufacturing Co. in 1882 and was last used in 1896. (Smithsonian photo 36716F.)
Figure 7.—The “Utility,” designed by Smith A. F. and constructed by Seth Wilmarth in 1854, was built to haul trains across the bridge at Harrisburg, Pa.
Figure 8.—The earliest known illustration of the Pioneer, drawn by A. S. Hull, master mechanic of the Cumberland Valley Railroad in 1876. It depicts the engine as it appeared in 1871. (Courtesy of Paul Westhaeffer.)
The Pioneer and Jenny Lind achieved such success in action that the president of the road, Frederick Watts, commented on their performance in the annual report of the Cumberland Valley Railroad for 1851. Watts stated that since their passenger trains were rarely more than a baggage car and two coaches, the light locomotives “… have been found to be admirably adapted to our business.” The Cumberland Valley Railroad, therefore, added two more locomotives of similar design in the next few years. These engines were the Boston and the Enterprise, also built by Wilmarth in 1854-1855.
Watts reported the Pioneer and Jenny Lind cost $7,642. A standard 8-wheel engine cost about $6,500 to $8,000 each during this period. In recent years, the Pennsylvania Railroad has stated the Pioneer cost $6,200 in gold, but is unable to give the source for this information. The author can discount this statement for it does not seem reasonable that a light, cheap engine of the pattern of the Pioneer could cost as much as a machine nearly twice its size.
Figure 9.—Annual pass of the Cumberland Valley Railroad issued in 1863.
Figure 10.—Timetable of the Cumberland Valley Railroad for 1878.
Service History of the Pioneer
After being put in service, the Pioneer continued to perform well and was credited as able to move a 4-car passenger train along smartly at 40 mph.[8] This tranquility was shattered in October 1862 by a raiding party led by Confederate General J. E. B. Stuart which burned the Chambersburg shops of the Cumberland Valley Railroad. The Pioneer, Jenny Lind, and Utility were partially destroyed. The Cumberland Valley Railroad in its report for 1862 stated:
The Wood-shop, Machine-shop, Black-smith-shop, Engine-house, Wood-sheds, and Passenger Depot were totally consumed, and with the Engine-house three second-class Engines were much injured by the fire, but not so destroyed but that they may be restored to usefulness.
However, no record can be found of the extent or exact nature of the damage. The shops and a number of cars were burned so it is reasonable to assume that the cab and other wooden parts of the locomotive were damaged. One unverified report in the files of the Pennsylvania Railroad states that part of the roof and brick wall fell on the Pioneer during the fire causing considerable damage. In June 1864 the Chambersburg shops were again burned by the Confederates, but on this occasion the railroad managed to remove all its locomotives before the raid. During the Civil War, the Cumberland Valley Railroad was obliged to operate longer passenger trains to satisfy the enlarged traffic. The Pioneer and its sister single-axle engines were found too light for these trains and were used only on work and special trains. Reference to table 1 will show that the mileage of the Pioneer fell off sharply for the years 1860-1865.
Table 1.—Yearly Mileage of the Pioneer
(From Annual Reports of the Cumberland Valley Railroad)
| Year: | Miles |
| 1852 | [a] 3,182 |
| 1853 | [b] 20,722 |
| 1854 | 18,087 |
| 1855 | 14,151 |
| 1856 | 20,998 |
| 1857 | 22,779 |
| 1858 | 29,094 |
| 1859 | 29,571 |
| 1860 | 4,824 |
| 1861 | 4,346 |
| 1862 | ( [c] ) |
| 1863 | 5,339 |
| 1864 | 224 |
| 1865 | 2,215 |
| 1866 | 20,546 |
| 1867 | 5,709 |
| 1868 | 13,626 |
| 1869 | 1,372 |
| 1870 | … |
| 1871 | 2,102 |
| 1872 | 4,002 |
| 1873 | 3,721 |
| 1874 | 3,466 |
| 1875 | 636 |
| 1876 | 870 |
| 1877 | 406 |
| 1878 | 4,433 |
| 1879 | … |
| 1880 | 8,306 |
| 1881 | ( [d] ) |
| Total | [e] 244,727 |
[a] Mileage 1852 for January to September (no record of mileage recorded in Annual Reports previous to 1852).
[b] 15,000 to 20,000 miles per year was considered very high mileage for a locomotive of the 1850’s.
[c] No mileage reported for any engines due to fire.
[d] Not listed on roster.
[e] The Pennsylvania Railroad claims a total mileage of 255,675. This may be accounted for by records of mileages for 1862, 1870, and 1879.
In 1871 the Pioneer was remodeled by A. S. Hull, master mechanic of the railroad. The exact nature of the alterations cannot be determined, as no drawings or photographs of the engine previous to this time are known to exist. In fact, the drawing (fig. 8) prepared by Hull in 1876 to show the engine as remodeled in 1871 is the oldest known illustration of the Pioneer. Paul Westhaeffer, a lifelong student of Cumberland Valley R. R. history, states that according to an interview with one of Hull’s descendants the only alteration made to the Pioneer during the 1871 “remodeling” was the addition of a handbrake. The road’s annual report of 1853 describes the Pioneer as a six-wheel tank engine. The report of 1854 mentions that the Pioneer used link motion. These statements are enough to give substance to the idea that the basic arrangement has survived unaltered and that it has not been extensively rebuilt, as was the Jenny Lind in 1878.
By the 1870’s, the Pioneer was too light for the heavier cars then in use and by 1880 it had reached the end of its usefulness for regular service. After nearly thirty years on the road it had run 255,675 miles. Two new passenger locomotives were purchased in 1880 to handle the heavier trains. In 1881 the Pioneer was dropped from the roster, but was used until about 1890 for work trains. After this time it was stored in a shed at Falling Spring, Pennsylvania, near the Chambersburg yards of the C.V.R.R.
Mechanical Description of the Pioneer
After the early 1840’s the single-axle locomotive, having one pair of driving wheels, was largely superseded by the 8-wheel engine. The desire to operate longer trains and the need for engines of greater traction to overcome the steep grades of American roads called for coupled driving wheels and machines of greater weight than the 4—2—0. After the introduction of the 4—4—0, the single-axle engine received little attention in this country except for light service or such special tasks as inspection or dummy engines.
There was, however, a renewed interest in “singles” in the early 1850’s because of W. B. Adams’ experiments with light passenger locomotives in England. In 1850 Adams built a light single-axle tank locomotive for the Eastern Counties Railway which proved very economical for light passenger traffic. It was such a success that considerable interest in light locomotives was generated in this country as well as in England. Nearly 100 single-axle locomotives were built in the United States between about 1845-1870. These engines were built by nearly every well-known maker, from Hinkley in Boston to the Vulcan Foundry in San Francisco. Danforth Cooke & Co. of Paterson built a standard pattern 4—2—4 used by many roads. One of these, the C. P. Huntington, survives to the present time.
The following paragraphs describe the mechanical details of the Pioneer as it appears on exhibition in the Smithsonian Institution’s new Museum of History and Technology.
BOILER
The boiler is the most important and costly part of a steam locomotive, representing one-fourth to one-third of the total cost. A poorly built or designed boiler will produce a poor locomotive no matter how well made the remainder of mechanism. The boiler of the Pioneer is of the wagon-top, crownbar, fire-tube style and is made of a 5/16-inch thick, wrought-iron plate. The barrel is very small, in keeping with the size of the engine, being only 27 inches in diameter. While some readers may believe this to be an extremely early example of a wagon-top boiler, we should remember that most New England builders produced few locomotives with the Bury (dome) boiler and that the chief advocates of this later style were the Philadelphia builders. By the early 1850’s the Bury boiler passed out of favor entirely and the wagon top became the standard type of boiler with all builders in this country.
Sixty-three iron tubes, 17/8 inches by 85 inches long are used. The original tubes may have been copper or brass since these were easier to keep tight than the less malleable iron tubes. The present tube sheet is of iron but was originally copper. Its thickness cannot be conveniently measured, but it is greater than that of the boiler shell, probably about 1/2 to 5/8 inch. While copper tubes and tube sheets were not much used in this country after about 1870, copper was employed as recently as 1950 by Robert Stephenson & Hawthorns, Ltd., on some small industrial locomotives.
The boiler shell is lagged with wooden tongue-and-groove strips about 21/2 inches wide (felt also was used for insulation during this period). The wooden lagging is covered with Russia sheet iron which is held in place and the joints covered by polished brass bands. Russia sheet iron is a planish iron having a lustrous, metallic gray finish.
Figure 13.—Advertisement of Seth Wilmarth appearing in Boston city directory for 1848-1849.
Click here for transcription of advertisement.
Figure 14.—The “Fury,” built for the Boston and Worcester Railroad in 1849 by Wilmarth. It was known as a “Shanghai” because of its great height. (Smithsonian Chaney photo 6443.)
Figure 15.—The “Neptune,” built for the Boston and Worcester in 1847 by Hinkley and Drury. Note the similarity of this engine and the Fury.
Figure 16.—The “Pioneer” as first exhibited in the Arts and Industries building of the Smithsonian Institution prior to restoration of the sandbox. (Smithsonian photo 48069D.)
[BOILER continued]
The steam dome (fig. 18) is located directly over the firebox, inside the cab. It is lagged and jacketed in an identical manner to the boiler. The shell of the dome is of 5/16-inch wrought iron, the top cap is a cast-iron plate which also serves as a manhole cover offering access to the boiler’s interior for inspection and repair.
Figure 18.—“Pioneer” locomotive, (1) Safety valve, (2) spring balance, (3) steam jet, (4) dry pipe, (5) throttle lever, (6) throttle, (7) crown bar, (8) front tube sheet, (9) check valve, (10) top rail, (11) rear-boiler bracket, (12) pedestal, (13) rocker bearing, (14) damper, (15) grate, (16) bottom rail, (17) pump heater valve, (18) cylinder lubricator, (19) reversing lever, (20) brake shoe, (21) mud ring, (22) blowoff cock, (23) ashpan. (Drawing by J. H. White.)
A round plate, 20 inches in diameter, riveted on the forward end of the boiler, just behind the bell stand, was found when the old jacket was removed in May 1963. The size and shape of the hole, which the plate covers, indicate that a steam dome or manhole was located at this point. It is possible that this was the original location of the steam dome since many builders in the early 1850’s preferred to mount the dome forward of the firebox. This was done in the belief that there was less danger of priming because the water was less agitated forward of the firebox.
The firebox is as narrow as the boiler shell and fits easily between the frame. It is a deep and narrow box, measuring 27 inches by 28 inches by about 40 inches deep, and is well suited to burning wood. A deep firebox was necessary because a wide, shallow box suitable for coal burning, allowed the fuel to burn so quickly it was difficult to fire the engine effectively. With the deep, narrow firebox, wood was filled up to the level of the fire door. In this way, the fire did not burn so furiously and did not keep ahead of the fireman; at the same time, since it burned so freely, a good fire was always on hand. The Pioneer burned oak and hickory.[14] For the firebox 5/16-inch thick sheet was used, for heavier sheet would have blistered and flaked off because of the intense heat of the fire and the fibrous quality of wrought-iron sheet of the period. Sheet iron was fabricated from many small strips of iron rolled together while hot. These strips were ideally welded into a homogeneous sheet, but in practice it was found the thicker the sheet the less sure the weld.
The fire grates are cast iron and set just a few inches above the bottom of the water space so that the water below the grates remains less turbulent and mud or other impurities in the water settle here. Four bronze mud plugs and a blowoff cock are fitted to the base of the firebox so that the sediment thus collected can be removed (figs. 17, 18).
The front of the boiler is attached to the frame by the smokebox, which is a cylinder, bolted on a light, cast-iron saddle (not part of the cylinder castings nor attached to them, but bolted directly to the top rail of the frame; it may be a hastily made repair put on at the shops of the C.V.R.R.). The rear of the boiler is attached to the frame by two large cast-iron brackets, one on each side of the firebox (fig. 18). These are bolted to the top rail of the frame but the holes in the brackets are undoubtedly slotted, so that they may slide since the boiler will expand about 1/4 inch when heated. In addition to the crown bars, which strengthen the crown sheet, the boiler is further strengthened by stay bolts and braces located in the wagon top over the firebox, where the boiler had been weakened by the large hole necessary for the steam dome. This boiler is a remarkably light, strong, and compact structure.
BOILER FITTINGS
Few boiler fittings are found on the Pioneer and it appears that little was done to update the engine with more modern devices during its many years of service. With the exception of the steam gauge, it has no more boiler fitting than when it left the builder’s shop in 1851.